U.S. patent number RE41,424 [Application Number 10/821,282] was granted by the patent office on 2010-07-06 for torque responsive actuation device.
Invention is credited to Steven R. Benson.
United States Patent |
RE41,424 |
Benson |
July 6, 2010 |
Torque responsive actuation device
Abstract
The invention is in a torque responsive actuation device,
preferably for a belt drive system as is commonly utilized with
snowmobile and like type vehicles. A bearing carrier of the
invention is connected to a lower half of a split pulley, with the
upper pulley half mounting a helix or cam cone that extends towards
the carrier undersurface and includes a plurality of cam tracks
formed therein that are each to receive a cam follower for travel
therealong. Movement of the bearing carrier towards the top face of
the pulley upper half is thereby translated to lower the pulley
half to spread the pulley upper and lower halves apart, opening a V
slot therebetween wherein a drive belt is maintained. A cylindrical
shaft is journaled through the bearing carrier and fitted through
the pulley that includes a coil spring disposed therearound for
providing spring biasing to urge the bearing carrier away from the
pulley upper half, biasing the pulley halves together. To provide
minimum friction operation and wear the invention employs cam
follower bearings as the cam followers and radiuses either the
outer surface of rollers of each cam follower bearing or of the cam
tracks to be convex and to have an apex that contacts and rolls
along a center line of the opposing surface, the roller of each
bearing to travel through a variety of cam angles during operation
of the torque responsive actuation device.
Inventors: |
Benson; Steven R. (Murray,
UT) |
Family
ID: |
24476979 |
Appl.
No.: |
10/821,282 |
Filed: |
April 8, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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08323611 |
Oct 17, 1994 |
5516333 |
|
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Reissue of: |
08618259 |
Mar 18, 1996 |
05720681 |
Feb 24, 1998 |
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Current U.S.
Class: |
474/10; 474/21;
474/12; 192/54.52; 192/93A |
Current CPC
Class: |
F16H
63/067 (20130101); F16H 55/56 (20130101); F16H
61/6625 (20130101) |
Current International
Class: |
F16H
55/36 (20060101); F16H 53/02 (20060101); F16H
55/56 (20060101) |
Field of
Search: |
;474/8-12,17,19,14,21
;192/93A,52.54 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Charles; Marcus
Attorney, Agent or Firm: Briggs and Morgan, P.A.
Parent Case Text
.Iadd.RELATED APPLICATIONS
This is a continuation-in-part of application Ser. No. 08/323,611,
filed Oct. 17, 1994, now U.S. Pat. No. 5,516,333. .Iaddend.
Claims
I claim:
1. A torque responsive actuation device comprising, a split pulley
having a pair of upper and lower pulley halves forming a V slot
therebetween to receive a drive belt; a cylindrical cam cone means
maintained to extend outwardly from a center of a top face of said
upper pulley half and including a plurality of equally spaced
identical right triangle cam sections each including a like sloping
cam track that extends along said right triangle hypotenuse side; a
shaft means extending from said lower pulley half; a carrier means
whereto are arranged a plurality of cam follower means that each
include a roller bearing means for each said sloping cam track,
with said carrier means maintained through a connector means to
said lower pulley half, .Iadd.said connector means including a
plurality of connectors spaced from a center of said lower pulley
half and projecting through an opening formed in said upper pulley
half, .Iaddend.and each said cam follower means .Iadd.and
.Iaddend.roller bearing means includes a roller journaled thereto
having a surface that contacts one of said sloping cam tracks, to
roll therealong, and either said roller contact surface or said
sloping cam track surface is radiused or crested, to be equally
curved or sloped downwardly from a highest point or surface of each
said sloping cam track to the sides of each said right triangle cam
section; and spring biasing means for urging said carrier means
away from said upper pulley half top face.
2. A torque responsive actuation device for a belt drive system as
recited in claim 1, wherein either the roller contact surface or
the sloping cam track surface is formed with a convex surface
between said roller sides or said cam track sides to have a radius
selected for the cylindrical cam cone cam track slope.
3. A torque responsive actuation device as recited in claim 2,
wherein either the roller contact surface or the sloping cam track
surface is formed to have a center apex therearound or therealong
wherefrom two like, oppositely sloping, flat surfaces slope to the
roller sides or the sloping cam track surface sides.
4. A torque responsive actuation device as recited in claim 1,
wherein the shaft means is a straight cylindrical shaft connected
at its lower end to the pulley lower half, passes through the
pulley upper half and connects, at its upper end to the carrier
means; and the spring biasing means is a coil spring disposed
around said straight cylindrical shaft between said upper pulley
half and said carrier means.
5. A torque responsive actuation device as recited in claim 1,
wherein the means for connecting the carrier means to the lower
pulley half are a plurality of equally spaced piers that each
include rods extending axially out of top ends thereof, which said
piers are each secured, at their lower ends, to said lower pulley
half hub, are each radially equidistant from the center of said
lower pulley half and will project at right angles through holes
formed in the upper pulley half, with ends of said rods secured to
said carrier means at approximately right angles to the
undersurface thereof.
6. A torque responsive actuation device for a belt drive system as
recited in claim 1, further including spaced holes formed through
the carrier means that are identical arcuate slots, are spaced
equally from one another, at equal radial distances from the
carrier means and are aligned for receiving the right triangle cam
sections fitted therein.
7. A torque responsive actuation device as recited in claim 1,
wherein the cylindrical cam cone is formed to have a bottom portion
for securing to the top face of the upper pulley half.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to clutch type systems and in particular to
a torque responsive actuation devices that include roller bearings
arranged to travel along helix tracks to open and closing opposing
pulley halves for a belt driven power train as is commonly used for
snowmobiles, and the like.
2. Prior Art
The present invention is in a torque responsive actuation device
that incorporated bearings arranged travel along helix tracks,
functioning as a clutch for a belt driven power train. The
invention improves upon prior systems by providing for radiusing
either the bearing or track whereon it travels, the bearing to
travel along a center line of the helix track, with bearing travel
to spread apart pulley halves wherearound a continuous drive belt
is positioned. The pulley opening is matched by closure of a drive
clutch. So arranged, based upon engine speed, the one clutch will
open its pulley, thereby reducing the radius of pulley that the
belt travels around, as the other clutch closes its pulley, thereby
increasing the pulley radius. The belt is tightly maintained within
the pulleys with changes in applied torque producing changes in the
radiuses of the respective clutch pulleys.
Examples of earlier devices for varying pulley diameter responsive
to torque are shown in U.S. Patents to: Steurer, U.S. Pat. No.
3,722,308; Togami, et al. No. 4,173,155; Huff, U.S. Pat. No.
4,378,221; Marier, U.S. Pat. No. 4,585,429; and Smith, et al, U.S.
Pat. No. 5,403,240. The desirability of decreasing friction and
diminishing binding between bearings and the helix tracks whereon
they travel was recently recognized in a patent application of the
present inventor, entitled "Torque Responsive Actuation Device for
a Belt Drive System" U.S. patent application Ser. No. 08/323,611,
filed Oct. 17, 1994, now U.S. Pat. No. 5,516,333 that the present
invention improves upon.
In applicant's earlier patent application, only the helix cam
tracks that individual roller bearing travel along were shown
radiused, each presenting a convex surface therealong. These curved
surfaces provide for centering the roller of each roller bearing as
it rolls therealong, providing for a very smooth clutch upshift and
backshift relative movement with less component wear than earlier
clutch arrangements experience. The present invention further
recognizes that any torque sensing type of clutch arrangement that
utilizes a bearing a cam can include a radiusing of either of the
opposing bearing or helix surfaces to obtain the benefits as set
out in the above cited U.S. Patent Application.
SUMMARY OF THE INVENTION
It is a principal object of the present invention in a torque
responsive actuation device to provide a torque sensing system that
is operated to produce near frictionless pulley ratio shift
changes.
Another object of the present invention is to provide a torque
responsive actuation device that is easily operated and provides a
high degree of torque sensitivity and efficiency so as to allow for
quick and precise upshifting and backshifting.
Another object of the present invention is to provide a torque
responsive actuation device with bearings that travel along
individual tracks of track sections of a helix or cam cone, with
either opposing bearing or track surface to have a convex surface
with a greatest diameter of the convex surface preferably at the
surface center so as to provide a point contact between the bearing
surfaces that will remain centered during travel of the one surface
over the other.
Still another object of the present invention is to provide a
torque responsive actuation device where either of the opposing
bearings or track surfaces have convex surfaces formed
thereacross.
Still another object of the present invention is to provide a
torque responsive actuation device for use in belt driven vehicles,
such as snowmobiles, or the like, where either of the individual
roller bearing contact surfaces are radiused thereacross that each
engage and roll along the center of a track, through a variety of
cam angles as could otherwise create side loads on the bearings,
thereby providing a torque responsive actuation device that will
exhibit easy, smooth, efficient and essentially frictionless
shifting over a long service life.
In accordance with the above objects of the present invention is in
a torque responsive actuation device as for example, for a belt
drive system that includes a pulley formed from upper and lower
halves that, when fitted together, form a deep V therebetween that
receives a drive belt disposed therein.
For the invention, bearings, as set out below, are arranged to
travel along each of a plurality of cam tracks, spreading apart
pulley halves to function as a clutch. With each bearing roller
centered on the cam track as it rolls therealong, avoiding track
edge wear and a possibility of a bearing roller binding at the
track edge from side loads, to provide bearing roller centering,
either the roller surface or the track surface is radiused
thereacross, or includes a center triangular pack therealong. The
radius or height of the surface is selected such that the roller
traveling along the track will follow a path along the track center
throughout a variety of cam angles. Though, it should be
understood, the invention can be in any clutch type device where
opposing bearing surfaces are fitted together with rollers, or the
like, to travel along tracks. In which arrangements, either the
roller or track surfaces are provided with a radiused surface of
apex to provide point contact therebetween that will remain
centered during travel.
In a first embodiment, an upper pulley half includes a center hole
and with spaced holes wherethrough piers from the lower pulley half
extend. The piers are equally spaced radially from the lower pulley
half center and project past the upper pulley half top surface.
Also mounted to extend upwardly from the upper pulley half top face
is a cylindrical helix or cam cone that includes at least three
identically equal spaced helix or cam sections formed therein. The
helix or cam sections are each equally spaced radially from the
upper pulley half center. The identical helix or cam sections are
preferably formed by appropriately machining a metal cylindrical
section to leave a flat bottom surface that is arranged to be
mounted to the upper pulley half top surface such that the helix or
cam cone extends at approximately a right angle outwardly
therefrom.
Each helix or cam section includes a cam track formed from a lower
corner at the junction of a cylindrical ring bottom end and upper
pulley half top face, and extending straight across the cylinder
segment to an upper distant corner thereof. Each cam track is
angled upwardly from the pulley half upper face, and is formed to
be flat thereacross.
The preferred roller bearings for this embodiment are preferably
three individual sealed needle bearing that are each journaled to
extend at right angles from the side of posts that are each
themselves secured at equal spaced radial intervals to extend
outwardly from an actuation or clutch cover plate assembly
undersurface. The posts are each adjacent to an arcuate slot that
has been formed through the actuator or clutch cover plate
wherethrough the helix of cam cone track sections project when the
clutch cover plate undersurface is moved towards the pulley half
upper face. The clutch cover plate is guided on a cylindrical shaft
that is journaled, at a right angle, through a bushing that is
maintained in a center hole of the clutch cover plate and a hole
formed through the pulley center.
For a second embodiment roller bearings are maintained across
cavities of a cylindrical bearing carrier, rolling along tracks of
a helix or cam cone. As with the first embodiment, the helix or cam
cone is mounted to, to extend upwardly from, the clutch cover plate
under surface, with the cylindrical bearing carrier function like
the clutch cover plate and is guided, like the clutch cover plate,
on the cylindrical shaft.
For both embodiments, the cylindrical shaft is secured to the upper
pulley half and is journaled through and extends beyond the lower
pulley half, with clutch cover plate, cylindrical bearing carrier
movement towards the upper pulley half top face to separate the
upper and lower pulley halves to operate the torque responsive
actuation device of the invention.
To urge the clutch cover plate cylindrical bearing carrier and
upper pulley half apart, a coil spring is preferably disposed over
the cylindrical shaft with the spring ends contacting the opposing
clutch cover plate, cylindrical bearing carrier undersurface and
upper pulley half top face, biasing them apart. This biasing is
overcome by moving the clutch cover plate, cylindrical bearing
carrier towards the upper pulley half, thereby separating the
pulley halves, to open the pulley V, reducing the radius
thereof.
THE DRAWINGS
The following drawings illustrate that which is presently regarded
as the best mode for carrying out the invention:
FIG. 1 is a first embodiment of a torque responsive actuation
device of the present invention, showing upper and lower pulley
halves closed together with a drive belt maintained
therebetween;
FIG. 2 shows the torque responsive actuation device of FIG. 1 as a
top plane perspective view to illustrate the operation thereof
where an actuator cover plate assembly is moved toward an upper
pulley half top face, thereby moving a lower pulley half away from
which upper pulley half, opening a V formed between which pulley
halves;
FIG. 3 is a bottom plan enlarged perspective view of the actuator
cover plate assembly of the torque responsive actuation device of
FIGS. 1 and 2;
FIG. 4 is a side elevational perspective view of the helix or cam
cone of the torque responsive actuation device of FIGS. 1 and 2
removed from its mounting onto the top face of the upper pulley
half;
FIG. 4A is a top plan sectional view taken along the line 4A--4A of
FIG. 4 showing the helix or cam track as radiused;
FIG. 4B is a view like that of FIG. 4A only showing the helix or
cam track as having a center apex with equal flat sides sloping
downwardly therefrom to intersect cam section sides;
FIG. 4C is a view like that of FIG. 4B only showing the helix or
cam track as having been flattened below the apex;
FIG. 5 is a top sectional view taken along the line 5--5 of FIG. 4
showing the flat surface of the helix or cam track and showing a
radiused cam follower roller journaled on an axle, shown in broken
lines, so as to extend outwardly from an upright post of the
actuator cover plate;
FIG. 5A is a view like that of FIG. 5 only showing the cam follower
roller having a center apex with equal flat sides sloping
downwardly therefrom to the roller side;
FIG. 5B is a view like that of FIG. 5A only showing the cam
follower roller as having been flattened below the apex;
FIG. 6 is a top plan view of the helix or cam cone of FIG. 4;
FIG. 7 is an exploded side elevational perspective view of a second
embodiment of a torque responsive actuation device of the present
invention showing upper and lower pulley halves separated with a
helix or cam track shown aligned for fitting to an upper pulley
half, and with a cylindrical bearing carrier aligned with a coil
spring and cylindrical shaft for mounting to a lower pulley
half;
FIG. 8 is an enlarged bottom plan view of the cylindrical bearing
or carrier of FIG. 7;
FIG. 9 is an enlarged side elevational perspective view of the
helix or cam cone of FIG. 7; and
FIG. 9A is an enlarged sectional view taken along the line 9A--9A
of FIG. 9.
DETAILED DESCRIPTION
FIGS. 1 and 2 show side elevation and top plan perspective views of
a first embodiment of a torque responsive actuation device 20 of
the invention, hereinafter referred to as actuation device 20.
While the actuation device 20 is a significant departure from
earlier driven clutch assemblies, its functions are similar to my
earlier U.S. Patent Application for "A Torque Responsive Actuation
Device for a Belt Drive System" Ser. No. 08/323,611 now U.S. Pat.
No. 5,516,333. Unique therefrom, however, is the configuration of
the respective cam follower bearing rollers and the cam tracks
wherealong the rollers travel, as set out and described herein.
According, it should be understood, the description of the Torque
Responsive Actuation Device of the above cited U.S. Patent
Application, and its functioning should be taken as a description
appropriate to the actuation device 20 of the present invention,
and accordingly the disclosure of this U.S. patent application Ser.
No. 08/323,611 now U.S. Pat. No. 5,516,333, is incorporated herein
by this reference. Similar to the above cited U.S. Patent
Application, the first and second embodiments of the present
invention include configuration of cam follower bearings that each
include a roller type device arranged for traveling along a helix
or cam track. The configuration of the roller surfaces or helix or
cam track of the earlier patent application and present invention
are to provide for minimizing wear and friction between components
and to preclude roller binding due to side loads as occur when a
roller travels to a track edge.
As with my earlier U.S. patent application Ser. No. 08/323,611 now
U.S. Pat. No. 5,516,333, for the actuation device 20, individual
actuator cover plate helix or cam track wear and roller binding are
dramatically improved by providing for a radiusing of each bearing,
as shown best in FIGS. 3, 4 and 5, to form a convex surface
thereacross. .[.Which.]. .Iadd.The .Iaddend.convex surface .[.to.].
.Iadd.may .Iaddend.have a greatest height at the bearing center, to
guide bearing travel along the center of the flat cam track, as
shown in FIG. 5. The roller center is thereby maintained
equidistant from the track edges. Heretofore,.[.,.]. earlier
arrangements.[.,.]. involved bearing and cam track surfaces that
were both flat with a path of travel of each clutch plate roller,
or, as in earlier arrangements slides, was from one cam track edge
to the other, creating side loads on the bearing or slides during
operation as the bearing or slide traveled through the varied cam
angles during travel over the cam track. Such side lobes produced
unequal roller or slide and cam track wear as the roller changed
position through varied cam angles during its travel from one cam
track side to the other, often causing bearing binding and damage.
Such earlier clutches.[.,.]. are both stiff and hard to operate and
have required frequent repair to replace worn slides or roller
bearings. Distant therefrom, the present invention provides an
actuation devices that provide smooth and easy operation, exhibit a
minimum of wear on cam follower bearing rollers, and provide for a
quick shifting at essentially a zero over-rev condition. Further,
as individual roller travel of the present invention remains
centered longitudinally along a cam track, side loads on each cam
follower roller as are present at the track edges that may cause
roller binding and damage are negated.
The actuation device 20, as shown in FIGS. 1 and 2, includes an
actuator cover plate 21, that is shown inverted in FIG. 3 from its
arrangement in FIGS. 1 and 2. As shown best in FIG. 2, the actuator
cover plate undersurface 22 is essentially parallel to an upper or
top face 24 of an upper pulley half 23a of a pulley 23. The pulley
23 consists of upper and lower pulley halves 23a and 23b,
respectively, that have, when closed together, a deep V that a
drive belt 25 will fit into. To provide pulley separation, reducing
the pulley effective radius relative to the drive belt 25 the lower
pulley half 23, as shown in FIG. 2, includes three piers 35 that
are each secured to a hub area, at equal spaced intervals and equal
radial distances from the lower pulley half center, and extend
through arcuate openings 30 that are formed through the upper
pulley half 23a hub area. The piers 35 each include a rod 36
extending axially from the top surface, that, in turn, are each
fitted through holes 37 formed through the actuator cover plate 21.
The holes 37, as shown in FIG. 3, are each stepped outwardly into
flat ledge 37a, and the rod 36 ends are stepped inwardly into a
flat shoulder. So arranged, each rod shoulder fits against a hole
ledge, and a rod end that extends through the hole 37 is threaded
to receive nut 38 turned thereover, for mounting the actuator cover
plate 21 onto rods 36, as shown in FIGS. 1 and 2. The actuator
cover plate 21 also includes a center hole 28 wherein a bushing 27
is shown fitted. The bushing 27 is to support travel of a straight
cylindrical shaft 26 between the attitudes shown in FIGS. 1 and 2.
As shown, the straight cylindrical shaft 26 extends, at a right
angle from the actuator cover plate 21 undersurface 22, and is
fitted through a center hole of the pulley 23. The cylindrical
shaft 26 is secured to the upper pulley half 23a to slide through
the lower pulley half 23b.
The cylindrical shaft 26, as set out above fitted through the
center bushing 27 is maintained in center hole 28 formed through
the actuator cover plate 21 to allow the cylindrical shaft to turn
or pivot relative to the actuator cover plate 21 during actuator
device 20 operation. This allows for actuator cover plate 21
pivoting or turning between the attitudes shown in FIGS. 1 and
2.
Movement of the actuator cover plate 21 towards the upper pulley
half 23a top face 24 is transferred through the connecting rods 36
and piers 35 to the lower pulley half 23b so as to move the pulley
23 halves apart, spreading the pulley V. .Iadd.As shown in FIG. 2,
each connector rod 36 is spaced away from the center of the lower
pulley half 23b and projects through an opening formed in the upper
pulley half 23a. .Iaddend.While the actuator cover plate 21 of
FIGS. 1 through 3, appears to be like and to function like the
actuator cover plate of my earlier cited U.S. Patent Application,
it should be understood that rollers 51, as shown best in FIG. 5,
are unique and distinct as set out and described hereinbelow.
In both the present and my earlier U.S. patent application the
actuator cover plate is moved towards the upper pulley half 23a top
face 24. To provide for actuator cover plate and lower pulley half
movement, the present invention and my earlier U.S. patent
application both include the radial equally spaced parallel piers
35 that are each secured to extend at right angles upwardly from
the hub area of the lower pulley have 23b, and pass through arcuate
holes 30 formed in the upper pulley half 23a. The piers 35 each
include the smooth walled cylindrical rod 36 that extends axially
from each pier top end. The cylindrical rods 36 are to fit through
that holes 37 that are formed at radial spaced intervals through
the actuator cover plate 21, as shown best in FIG. 2. So arranged,
the actuator cover plate 21 is maintained to the lower pulley half
23b and will slide up and down along cylindrical shaft 26 pivoting
or turning relative to the cylindrical shaft 26, when traveling
between the attitudes shown in FIGS. 1 and 2, to open the pulley
23, as described above.
With the actuator cover plate 21 secured onto each of the connected
rods 36, as set out above, a coil spring 39 is provided to bias the
actuator cover plate 21 outwardly, as shown in FIG. 1. To provide
for the pulley halves 23a and 23b being normally closed together,
the coil spring 39 is disposed around the cylindrical hub 26. So
arranged, the ends of coil spring 39 engage, respectively, the
undersurface 22 of the actuator cover plate 21 and the top face 24
of the upper pulley half 23a. The coil spring 39 thereby urges the
actuator cover plate 21 outwardly to where the halves of pulley 23
are closed together, as shown in FIG. 1. The biasing of coil spring
39 is overcome to urge the actuator cover plate towards the upper
pulley half, spreading the pulley 23 V, as shown in FIG. 2.
My cited U.S. Patent Application, and the actuation devices 20 and
70 of the invention all preferably employ a helix or cam cone
whereon are formed cam tracks that are each for guiding cam
followers. A helix or cam cone 40 of the actuator device is shown
best in FIG. 4 and as sections in FIGS. 4A, 4B, 4C, 5, 5A and 5B
with a helix or cam cone 77 of the actuation device 70 shown best
in FIG. 9, both having been removed from their mounting,
respectively, to the top or upper face 24 of the pulley half 23a
and a hub of pulley half 72.
Each helix or cam cone 40, shown in FIGS. 4 and 6, and 72 shown in
FIGS. 7 and 9, is preferably formed from a metal cylinder wherefrom
sections of material are removed to leave for the helix or cam cone
40, a base ring 41 that includes a flat bottom surface and a
mounting slot, respectively. The base ring 41 is stepped outwardly
at equal radial points along a top surface thereof into spaced
platforms 42 wherein are formed straight bolt hole 43 that extend
therethrough. The bolt holes 43 are each to receive a bolt 44,
shown in FIGS. 1 and 2, fitted therethrough. The bolts 44 are
turned into holes, not shown, that have been formed in the upper or
top face 24 of the upper pulley half 23a, mounting the helix or cam
cone 40 thereto. Adjacent to each platform 42, the helix or cam
cone is stepped outwardly into a cam section 45 that, as shown best
in FIGS. 4 and 6, is essentially a right triangle and includes a
straight cam track 46 as the right triangle hypotenuse side.
Each cam track 46 of the actuator device 20 is flat between the
edges thereof and in FIG. 4 and is radiused at 46c in FIG. 4A has a
center apex 46d with downwardly sloping sides 46e and 46f extending
therefrom to intersect cam track edges 46a and 46b in FIG. 4B, and
shows, in FIG. 4C, the apex as having been milled, of otherwise
formed, into a flat surface 46g. The respective track 46 surfaces
of 4, 4A, 4B and 4C to receive the roller 51 of a cam follower
roller bearing 50 positioned for travel therealong. In this
embodiment, each track is to receive a convex outer surface of
roller 51 of FIG. 5, or an apex 51d of a surface of roller 51, as
shown in broken lines in FIG. 5a, or a flattened apex 51e of a
surface of roller 51, shown in broken lines in FIG. 5B. For which
convex surface, the greatest diameter of cross section of the
roller 51 is to be positioned at the center of the cam track 46
between edges 46a and 46b thereof, and is to travel along the cam
track center as it rolls up and down therealong. Accordingly, the
radius of the convex curved 51c, apex 51d or flattened apex 51c
surface of each roller 51 preferably has a greatest diameter at the
roller lateral center 51c, shown in broken lines in FIGS. 3 and 5,
with apex 51d ad flattened apex 51e shown in broken lines in FIGS.
5A and 5B, respectively and curves or slopes uniformly therefrom to
the roller 51 ends 51a and 51b. It should be understood, however,
that the roller 51 greatest diameter can be at a location
therealong other than the center 51c, within the scope of this
disclosure. The determination of the preferred location of the
roller surface greatest diameter 51c, 51d or 51e, is to position it
between track 46 inner and outer edges 46a and 46b, respectively,
to provide a path of travel of a roller 51 of a cam follower
bearing 50 that will remain centered on the cam track 46 along its
entire path of travel. For the center of roller travel along the
length of track 46 to be equidistant from the cam track edges 46a
and 46b, the radius of the helix or cam cone 41 and the roller 51
are selected such that a roller 51 an appropriate radius of
curvature is provided for the roller surface taking into account
the varied cam angles that the cam follower roller will experience
as it travels therealong.
For the actuation device 20, the selection of a surface radius for
the roller 51 convex curve is based on the cam track 46 slope that,
of course, is also a helical curve that follows the curve of the
helix or cam cone 40. The cam track 46 may be formed to have from a
thirty degree (30.degree.) to seventy degree (70.degree.) slope and
that slope may itself vary along the track length. Shown herein,
the track 46 has approximately a fifty degree (50.degree.) slope.
For which slope a radius of curvature of the roller 51 surface of
approximately one (1) inch was selected for a track width of 0.325
inches and less, thereby producing, at the roller 51 center 51c, an
arc with a width of 0.26 inches and a drop of 0.0089 inches from
the roller center to its ends 51a and 51b. This drop of 0.0089
inches is preferred for any cam track slope as set out above, with
the roller 51 radius to be selected accordingly.
As set out above, as an alternative arrangement to the actuation
device 20, the roller 51 surface can be formed to have opposing
equal flat sloping sides that slope together at an apex 51d or
flattened apex 51e, as along the roller center 51c. Like the
selection, as set out above, of the radius for a particular slope
of track 46, taking into account that the track is also a helical
curve, the slope of roller 51 sides is selected to provide an apex
51d or flattened apex 51e at the roller 51 center 51c, or at a
location thereacross, such that the roller 51 will roll smoothly
along the track 46 center line during actuation device 20
operation. Accordingly, for the actuation device 20, it should be
understood that the individual rollers 51 surfaces can be radiused
or can be formed with opposing sloping sides that meet in apex, or
the like, as described. A roller contact surface is thereby
provided to center the roller along the cam track length precluding
application of side loads on the cam roller bearing 50 through
roller 51 as it travels therealong.
For the actuation device 20, each cam follower bearing 50 that
includes the roller 51, as shown best in FIGS. 3 and 5 and
described above, is shown as mounted on to a shaft 54. Each shaft
54 is fitted through each of three posts 52 that extend at right
angles outwardly at equidistance radial distance intervals from one
another around the center of the undersurface 22 of the actuator
cover plate 21. Each post 52, as shown, is preferably formed at a
flat section having a regular pyramid profile is connected to the
actuator cover plate undersurface along its base and has a rounded
apex that includes a hole 53 formed therethrough, as shown best in
FIG. 5, that receives a shaft 54 fitted therethrough. Each shaft 54
preferably includes a broad flat head end 55, and is press fitted
through hole 53 through post 52 to receive a connector 56 fitted
thereover. The shaft 54 is part of the cam follower bearing 50,
that includes roller 51 and is journaled to turn freely on the
sealed needle bearing 58, as shown in broken lines in FIG. 5.
As set out above, and as shown in FIGS. 3 and 5, the roller 51
curved surface will travel up and down along cam track 46,
following a center path therealong. The roller 51 is at rest at
approximately the top of cam track 46. During actuation device 20
operation, to spread apart the pulley halves 23a and 23b as shown
in FIG. 2, as the roller descends along the cam track 46 each cam
track top end, that is the apex end of each cam section 45, will
pass through one of three arcuate slots 47 that have been formed
through the actuator cover plate 21. The arcuate slots 47 are
spaced equidistantly apart and are at equal radial distances from
the actuator cover plate center. The cam sections 45 are to retract
through the arcuate slots 47 when pressure to move the actuator
cover plate 21 undersurface 22 towards the face 24 of the upper
pulley half 23a is released. The coil spring 39 is provided to
return the actuator cover plate 21 to the attitude shown in FIG.
1.
The second embodiment of the actuation device 70 is shown in FIGS.
7 through 9 and 9A. Similar to actuation device 20, in FIG. 7, the
actuation device 70 is shown to include a pulley 71 having lower
and upper pulley halves 72 and 73, respectively. Like the lower and
upper pulley halves 23a and 23b of the actuator device 20, the
pulley is to receive a drive belt, not shown, fitted therebetween.
With, upon operation of the actuation device 70, the surfaces of
the pulley halves will move apart and back towards one another
changing the pulley radius that the belt turns around. This
provides, like the actuation device 20, for a smooth shifting upon
torque sensing, functioning essentially like the actuation device
20.
A cylindrical shaft 74 is mounted axially to extend upwardly from
the center of the lower pulley half 73 to pass through a larger
center opening 75 that is formed through the upper pulley half 73
hub area. Pulley hub opening 75 includes a plurality of straight
pointed fingers 76 that, as set out below, are each for fitting
into one of slots 83 formed in a helix or cam cone 77. A coil
spring 78 is shown aligned for fitting in the hub opening 75 in the
upper pulley half 73 fitted around the cylindrical shaft 74. With a
top end 78a of coil spring 78 for engaging the undersurface of a
cylindrical bearing carrier 79. In FIGS. 7 and 9, the helix or cam
cone 77 is shown to include a lip 80 that is formed around the
lower end thereof adjacent to a groove 81 formed around the lower
portion thereof. The lip 80 is for fitting, as shown best in FIG.
7, within hub opening 75, of the upper pulley half 73. With the
finger 76 to fit the helix or cam cone 77 slots 83. The cam cone 77
is thereby mounted at a right or normal angle from the top surface
of the upper pulley half 73. The coil spring 78 is for fitting
therethrough and for engaging a lower end of cylindrical bearing
carrier 79, as set out hereinbelow.
Like the above described helix or cam cone 40 of the first
embodiment, the helix or cam cone 77, as shown best in FIG. 9,
includes a plurality of cam tracks 84, shown herein as three
tracks. Like the cam tracks 46, the cam tracks 84 are each of the
hypotenuse side of a right triangle, with a side 85 thereof shown
as vertical and the base the cross section extending between the
lower ends of which vertical side 85 and the hypotenuse side 84. As
shown in FIGS. 7 and 9, the helix or cam cone 77 is preferably
formed from a cylinder that is machined appropriately to form the
respective hypotenuse and vertical sides 84 and 85, as set out
above. For this embodiment, as shown in FIG. 9A, the track surfaces
84 are preferably each radiused, the curvature of which surface is
like that set out in applicant's earlier patent application, and is
computed, as described above for the radiusing the rollers 51 for
the actuation device 20. The track surfaces 84 of the actuation
device 70, as set out and described above, provide for maintaining
a bearing roller centered during travel therealong.
The tracks 84 are to receive rollers 95 of bearings 94 of the
cylindrical bearing carrier 79, as shown in FIGS. 7 and that will
therealong. The cylindrical bearing carrier, as shown, 8, is
preferably an arrangement of an outer cylinders 86 and an inner
cylinder 87 respectively, that are connected by strut sections 88.
The strut sections 88 connect into a shelf 89 that extends at a
right angle from the inner cylinder 87, as shown best in FIGS. 8
and 9. A plurality of spaced holes 90 are formed in the shelf 89,
as needed, for receiving top end 78a of coil spring 78 fitted
therein, with the opposite coil spring end 78b for fitting into a
hole formed in the hub area of the upper pulley half 73, not shown.
The inner cylinder 87 is open therethrough at 91, and includes a
longitudinal keyway 92 formed along its length. Curved arcuate
longitudinal openings 93 are provided between the opposing surfaces
of the outer and inner cylinders 86 and 87 that accommodate the
tracks 84 of the helix or cam cone 77. The openings 93 accommodate
the helix or cam cone 77 tracks 84 as the move up and down therein,
in which movement rollers 95 of bearings 94 engage and roll along
the respective track surfaces 84.
The bearings 94, as shown, are mounted between the inner and outer
sleeves 87 and 86, respectively, each on a shaft 96, that is shown
in broken lines in FIG. 8. Split ring 97 and washer 98 are provide
for fitting into a top groove 74b, the split ring 97 to hold the
washer 98 against the top surface of the inner cylinder 87 and with
the bottom of the inner cylinder connected to the coil spring 78,
as set out above. The cylindrical bearing carrier 79 is secured
onto the cylindrical shaft 74. To prevent cylindrical bearing
carrier pivoting a key, not shown, is fitted between into keyway
74a that is formed in the cylindrical shaft 74, and the keyway 92,
prohibiting rotation. So arranged, the vertical movement of the
cylindrical bearing carrier 79 moves also the lower pulley half 72
against the biasing of spring 78. Thereby, the roller 95 or
bearings 94 traveling down the sloping tracks 84, moving the
respective pulley halves 72 and 73 apart. With movement of the
cylindrical bearing carrier 79 upwardly, causing the bearing 94
rollers 95 to travel upwardly along the tracks 84, moving the
respective pulley halves together.
As set out above, the cylindrical bearing carrier 79 mounts onto
the end of cylindrical shaft 74 such that, when the assembly is
moved, by the bearing 94 roller 95 traveling along the tracks 84,
the cylindrical shaft 74 will be moved also. The pulley halves 72
and 73 are thereby separated or brought together, functioning as
described hereinabove with respect to the discussion of FIGS. 1 and
2.
In practice, a depression of the cylindrical bearing carrier 79,
against the biasing of coil spring 78, will cause the rollers 95 of
bearings 94 to travel down the tracks 84, acting through on the
cylindrical shaft 74 to spread apart the pulley halves 72 and 73.
Whereas, when a pressure is released from off the cylindrical
bearing carrier 79 the coil spring 78 acts to move the rollers 95
of the bearings 94 back up the tracks 84, returning the pulley
halves 72 and 73 to the attitude shown in FIG. 1.
Actuation devices 20 and 70, as wet out hereinabove, include,
respectively, radiused configurations of roller 51 surface and a
radiusing of tracks 84, respectively. In each of these
configurations the opposing surface to the roller or track is flat.
Accordingly, it should be understood that the invention is in any
torque responsive device that provides for travel of opposing
surfaces over one another to effect operation thereof, where one of
those opposing surfaces is radiused and the other is flat.
Accordingly, it should be understood that the invention is not
limited to a particular actuation device, as shown and described
herein, and includes any torque responsive device where one of the
opposing track and bearing surfaces is radiused, within the scope
of this disclosure.
While preferred embodiments of my invention in torque responsive
actuation devices for a belt drive system have been shown and
described herein, it should be understood that the present
disclosure is made by way of example only and the invention is
suitable for a number of uses, including, but not limited to, a use
as a snowmobile clutch system, and the like, and that variations
and changes to the torque responsive actuation device as described
are possible without departing from the subject matter coming
within the scope of the following claims, and a reasonable
equivalency thereof, which claims I regard as my invention.
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