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Патент USA US3304598

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Feb- 21, 1967
D A. HAUSMANN
IMPACT-ACTUATEf) SPRING SYSTEM FOR PRODUCING
3,304,591
VIBRATIONS IN A ROTATING FORM
Filed June 8, 1964
2 Sheets-Sheet l
INVENTOR,
054 5A’? )4. MrwA/mm/
BY
Afr-news)?
, Feb. 21, 1967‘
o. A. HAUSMANN
Filed June‘ 8,
IMPACT-ACTUATED SPRING SYS
VIBRATI ONS IN A HOT
1964 ‘
FOR PRODUCING
NG FORM
'
3,304,591 _
‘
2 Sheets-Sheet 2
INVENTOR.
?lziiifi, Mai/$14M”
BY
Irma/n1;
United States Patent C) if
'
3,3M,5l591
Patented Feb. 21, 1967
1
2
3.304591
the form and transmitting them to the form with a
minimum loss of power and maximum amplitude.
It is a further object of this invention to provide a
llMPACT-ACTUATED SPRING SYSTEM FOR PRO
DUCING VIBRATIONS IN A RQTATING FORM
Delbert A. Hausmann, Glendale, €alif., assignor to Ameri
can Pipe and Construction Co., Monterey Park, Calif”
vibrational system for rotating devices in which the
motive power is supplied by the rotation of the device
itself.
It is another object of the invention to provide a vibra
a corporation of California
Filed June 8, 1964, Ser. No. 373,454
6 Claims. (Cl. 25-30)
tional system for rotating devices in which the vibration
is generated by a spring system impelled in synchronism
This invention relates to a method of producing
with its natural frequency into continuous half-wave
vibrations in a rotating form or analogous device, and 10 vibrations, by motive means spacedly mounted on the
more particularly to a system in which vibration is im
device itself.
parted to the form by the impact of a spring-impelled
It is a still further object of the invention to provide
member, and the spring-impelled member in turn is set
a vibrational system of the type described in which the
in oscillation by impact thereagainst of protuberances
vibrational force is adjustable.
judiciously spaced around the periphery of the rotating 15
It is still another object of the invention to provide a
form. Although described herein speci?cally in connec
system of the type described which permits the use of
tion with a centrifugal casting process for concrete pipes,
several independent vibratory units on the same device
the method may be applied to the centrifugal casting of
without mutual interference.
other materials and to other processes requiring simul
These and other objects of the invention will become
20 apparent from a perusal of the following speci?cation
taneous vibration and rotation.
-Up to the present time, vibration of a rotating form
taken in connection with the accompanying drawings, in
has usually been accomplished with a power-driven high
which:
frequency vibrator or oscillator mounted either directly
FIG. 1 is a side elevation of the device of this inven
tion; and
on the form, or on an external wheel or shoe in contact
with the form. The ?rst method is unsatisfactory be 25
FIG. 2 is a vertical section, partly broken away along
cause of di?‘iculties in transmitting power to the rotating
line 2—-2 of FIG. 1.
'
vibrators and because vibrations are produced only at
Basically, the system of this invention consists of pro
?xed locations on the form. The second method is in
viding cams around the perimeter of a rotating form or
e?icient because the frequency of the powered vibrator
similar device. As the form rotates, the cams rhythmi
is generally much higher than the natural frequency of
the external mounting system, a condition which sup
cally propel a stationary impact wheel away from the
presses the amplitude of vibration of the contact wheel
or shoe. Also, much of the energy supplied to the
vibration is lost in viscous and frictional damping in the
ming momentum is expended, the spring rebounds the im
pact wheel against the form, only to encounter another
cam which again propels it away. If the angular velocity
vibrator mounting system.
form against the bias of a spring.
As soon as the cam
35 of the mold and the cam spacing is so related to the
The present invention overcomes these di?iculties and
natural frequency of the spring system that the rebound
ine?iciencies of the prior art by providing a stationary,
impact occurs precisely as the impact wheel encounters
adjustable-bias vibrating spring system which impacts
the leading edge of the next following cam, the system
uniformly around the perimeter of the form as it rotates,
sustains its vibrations with maximum efficiency and ampli
40
and whose motive power is supplied by the camming
tude and hence with a minimum of camming energy.
action of cams or protuberances judiciously spaced
Referring now to the drawings, the rotating form is
around the perimeter of the form to synchronize the
shown at 10. It rests on pairs of support wheels 12 and
impact repetition rate with the natural frequency of the
drive wheels 14, the latter of which are powered by a
spring to provide maximum amplitude and power utiliza
motor 16. The perimeter of the form 10 carries one or
. tion.
The system of the invention has been empirically
proven to be very effective in consolidating both granular
and plastic materials, and it will be readily understood
by those skilled in the art that it has the following ad
vantages over the prior art: (1) vibrations are trans
45
more rings 18, 20 which in turn are provided with cams
or protuberances 22.
Bearing against the surface of rings
18, 20 and against the cams 22 are impact wheels 24. The
impact wheels 24 are biased against the rings 18, 20 by
50 springs 26 contained within the telescoping cylinder mem
bers 28, 30. Wedges 32 operated by hydraulic controls
mitted uniformly around the circumference of the form;
(2) any desired impact frequency can be producedby
proper selection of spring, wheel assembly weight, and
34 permit the impact Wheels to be moved into and out of
contact with the form 10. The static biasing force with
which the wheels 24 are biased against the surface of the
cam spacing; (3) no separate power source is required
rings 18, 20 can be adjusted by means of the set screw 36.
for the impact system; (4) all energy required to com 55
It will be noted that the cams 22 on ring 18 are dis
pensate for damping losses is supplied by the rotating
placed by one-half their perimetric interval from those on
form through impact of the cams; (5) the system of
ring 20. The purpose of this arrangement is to prevent
this invention transmits a higher percentage of the vibra
mutual interference between the vibrations set up by the
tion force to the rotating mass than the systems of the
two vibrating systems——i.e., the impact on ring 18 occurs
prior art, with a consequent minimal loss of energy 60 while the wheel 24 associated with ring 20 is out of con
through the mounting means to the support frame; and
tact with the ring 20 at the end of its compressive stroke
(6) the impact strength is adjustable. In addition, when
(dot-dash line position of wheel 24 on FIG. 2), and vice
two impact units are operated against the same rotating
versa.
form, interference between vibrations from the two
Operation
sources can be eliminated by locating the cams on one 65
band one-half space out of phase with the cams on the
When the spring-mounted impact wheel 24 is brought
second band. This phase-shift principle can be extended
into contact with the form 10, it is impacted in sequence
to any number of impact units.
by each of the cams 22 on the ring 18 or 20. After each
It is therefore the object of this invention to provide
impact, the wheel 24 describes one-half cycle of simple
a vibrational system for rotating devices capable of_dis 70 harmonic motion as it is driven downward against the
tributing vibrations uniformly around the perimeter of
spring 26 and rebounded by it against the ring 18 or 20.
3,304,591
4
6
6
The period of time required for each impact cycle is a
function only of the natural frequency of the spring sys
w
3 — TREE:
tem and can thus be calculated from the known mass and
spring de?ection constant of the vibrating system.
For maximum effectiveness, the cams 22 can be spaced
so that the frequency with which they pass the impact
3
wheel 24 is exactly equal to twice the natural frequency
of the spring system. When this condition is satis?ed the
impact wheel develops its maximum amplitude and de
scribes a continuous series of half-sine waves with im
( 12)
Since the total number of carns is
27R
Substitution in Equation 12 gives
wn
"-217
10
pact occurring between each Wave.
Assuming a rotating form 10 having rings 18, 20 of
radius R which in turn carry a series of equally spaced
(13)
Example
Form diameter=23", R=1l.5 in.
peripheral earns 22 so arranged that each strikes in se
Spring factor, K: 1000 lb./in.
quence and with equal force a spring-supported wheel 24 15 Vibrating weight (including 1/2 spring wt.), w=50 lb.
Form operating speed to be approximately 135 rpm.
of eifective mass m. Assume the impact delivered by
each cam 22 drives the wheel 24 downward at an initial
From Equation 2
velocity V0. Neglecting viscous damping and other losses,
the change in kinetic and potential energy of m is equal
to work done by the spring in opposing motion. Thus
V: velocity after displacement x,
kzspring factor in pounds per inch deflection, and
x0: static spring de?ection.
Since
kxo=mg
_135(21r)
=14.l
60
w_
25
From Equation 13 the number of cams required is
w,,_
(2)
30
.
_
_.
Provide 12 cams at
_,2lr_
s—
12 -6.02 H
tem is
I?
88.0
TI’—2E——2(14-1 —12.0
and the natural frequency of the undamped spring sys
wax/E radians per second
radians/sec.
Most effective operating speed is
(3)
Equation 1 reduces to
(4)
It will be seen that the present invention provides an
At maximum displacement x1, V=0, and from Equation 4
V2____Vo2__wn2x2
extremely simple, efficient and adjustable method of vi
brating rotating forms. Obviously, the concept of the
Vozwnxl
(5)
invention can be carried out in many different ways, of
which the embodiment shown and described herein is
so that Equation 4 can be rewritten
V=wn\/:c12—x2
merely illustrative. Therefore, the invention is not to be
(6)
deemed limited by the foregoing description, but only
It is evident from Equations 5 and 6 that, from the time 45 by the scope of the following claims.
What I claim and desire to secure by Letters Patent
of impact until the wheel 24 again contacts the ring 18
or 20, the sprung mass oscillates in simple harmonic mo
is:
1. In combination with a rotating form, a vibrating
tion for which the displacement at time t is
x=x1'sin wnt
system comprising: stationary resilient means; impact
(7)
means carried by said resilient means and resiliently
biased thereby into engagement with said rotating form;
and the velocity is
da;
V=E=wnxycos wnt
and means on said rotating form for engaging said im
pact means to compress said resilient means in synchro
(8)
At maximum displacement
nism with twice the natural frequency of said resilient
55
means.
2. In combination with a rotating form, a vibrating
cos wnt1=0
system comprising: stationary resilient means; impact
and
means carried by said resilient means and resiliently
biased thereby into engagement with said rotating form;
w t —I
n 1"‘2
60
During the rebound portion of the cycle all energy gained
by the spring is expended in restoring the original poten
tial and kinetic energy of mass m.
Equations 7 and 8
apply, and the period for a complete cycle is thus twice
the time given by Equation 9, or
and equally spaced protuberances around the perimeter
of said rotating form arranged to engage said impact
means to compress said resilient means in synchronism
with twice the natural frequency of said resilient means.
3. In combination with a rotating form arranged to
rotate at a predetermined angular velocity, a vibrating
system comprising: stationary resilient means, impact
means carried by said resilient means and resiliently
biased thereby into engagement with said rotating form;
and equally spaced protuberances around the perimeter of
To insure that all actuating cams 22 strike in sequence,
the center-to-center cam spacing s should be equal to the 70 said rotating form arranged to engage said impact means
peripheral distance traveled during one impact cycle, i.e.,
s=RwT
(11)
where w is the angular velocity in radians per second, or
.from Equation 10
to compress said resilient means at twice the natural
frequency of said resilient means when said form is ro
tating at said predetermined angular velocity.
4. In combination with a rotating form, a vibrating
75 system comprising: stationary resilient means adjacent
3,304,591
5
6
each end of said rotating form; impact means carried by
thereby into engagement with said rotating form adjacent
each of said resilient means and biased thereby into en
the ends thereof; equally spaced cam means around the
gagement with said rotating form; and equally spaced
periphery of said rotating form adjacent each end there
camming means around the perimeter of said form ad
jacent each end thereof arranged to periodically engage
of arranged to engage said impact wheels to compress
said resilient means at twice the natural frequency of
said resilient means when said form is rotating at said
said impact means to compress said resilient means upon
rotation of said form; the leading edges of said camrning
predetermined angular velocity; and means for vary
means adjacent one end of said form being perimetrically
ing the force biasing said impact wheel against said form;
spaced from the leading edges of said camming means
the leading edges of said cam means adjacent one end
adjacent the other end of said form by one-half the peri 10 of said mold being perimetrically spaced from the lead
metric distance between adjacent camming means.
ing edges of said cam means adjacent the other end of
5. In combination with a rotating form arranged to ro
said mold by one-half their perimetric interval.
tate at a predetermined angular velocity, a vibrating
system comprising: stationary resilient means; impact
wheel means carried by said resilient means and resilient
ly biased thereby into engagement with said rotating
References Cited by the Examiner
UNITED STATES PATENTS
15
form; equally spaced cam means around the periphery
of said rotating form arranged to engage said impact
763,329
1,199,997
wheel to compress said resilient means at twice the
natural frequency of said resilient means when said form 20
1,992,739
2/ 1935
Carrington __________ __ 25-30
2,703,916
3/1955
Butler ______________ _. 25——3O
is rotating at said predetermined angular velocity; and
means for varying the force biasing said impact wheel
against said form.
6. In combination with a rotating form arranged to
rotate at a predetermined angular velocity, a vibrating
4,843/ 26
227,190
6/1904
10/1916
Rowntree ___________ __ 25-41
Lienesch ___________ .__ 25--3O
FOREIGN PATENTS
11/ 1927 Australia.
3/ 1960 Australia.
system comprising: stationary resilient means adja 25 J. SPENCER OVERHOLSER, Primary Examiner.
G. A. KAP, R. D. BALDWIN, Assistant Examiners.
cent each end of said form; impact wheel means carried
by each of said resilient means and resiliently biased
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