Improvements in Speed-indicators.
Year: 1897

page_text: Date of Application, 13th July, 1897-Accepted, 21st Aug., 1897
COMPLETE SPECIFICATION.
Improvements in Speed-indicators.
I, ALBERT LYMAN PARCELLE, of No. 157 Washington Street, Boston, in the
County of Suffolk and State of Massachusetts, United States of America,
Electrician, do hereby declare the nature of my invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:-
The invention consists in a speed indicating or measuring device of simple,
durable, and novel construction or character, the said device being adapted to be
attached to or used in connection with shafting or machinery having a rotary
motion, to indicate the speed of revolution, or in connection with the wheel or
axle of a vehicle of any description, such for example as that of a bicycle, to
indicate the rate of speed at which the vehicle is travelling. It is of a character
which enables it to work easily and without interfering at all with the easy running
of the bicycle. It is constructed with the utmost degree of simplicity, has
exceedingly little liability to wear, and is not liable to have its normal operation
disturbed by jolting so as to indicate temporarily a false rate of speed.
The invention will be described first with reference to the accompanying draw-
ing, in which I have represented the best embodiment thereof that I have yet
contrived, after which the distinguishing characteristics of the invention will
be particularly pointed out and distinctly defined in the claims at the close of this
specification.
Figure 1 of the drawing is a view of the said embodiment of my invention,
the parts thereof being mainly in vertical section on the dotted lines 1, 1, of
Figure 2.
Figure 2 is a view showing the said embodiment in elevation, looking from the
right in Figure 1.
Figure 3 is a view in section along the line 3-3 of Figure 1, looking from the
right in the latter figure.
Figures 4 and 5 are views in detail, showing a modification, Figure 4 being
sectional.
At 1 is a suitable case, and at 2 is a tubular support for the said case, only
a portion of the said tubular support being shown. At 3 is a glass cover having
a suitable metallic rim 4, the flange of the said rim entering the top of the case 1,
as shown most clearly in Figure 1. Any suitable form, construction, or character
of case, support, and cover may be employed, according to the taste of the maker
and the requirements of the use to which the device is to be applied. At 5 is
a small rod or spindle, which is located within the support 2. In practice, the
said rod or spindle is driven by or from the rotating part which is to have its
speed ascertained or indicated. The driving of the said rod or spindle by or
from the said rotating part may be effected in any known or suitable manner
not necessary to be shown or described herein. 6 is a disk mounted upon the
said rod or spindle 5 and turning therewith, the end of the said rod or spindle
projecting beyond the said disk. 7 is a small segment-gear located at the side

page_text: 8 is an
9 is a
When
of the disk 6, it fitting loosely upon the end of the rod or spindle 5.
inclined cam which is formed or fixed on the side of the said gear 7.
reversely placed inclined cam, the face of which bears against the face of the
cam 8. This inclined cam 9 is connected with the rod or spindle 5 in a manner
which causes it to rotate in unison with the latter, while leaving it free to move
lengthwise thereof. Any suitable or known means may be employed to this end.
In the drawing, I have shown the rod or spindle 5 as slabbed away at 10 (see
Figure 4), the cam 9 having a pin 11 passed therethrough, and the said pin
engaging with the flat surface which is produced on the rod or spindle. At 12
is an arm which is pivoted to the disk 6 near the edge of the latter, as at 13
(Figure 3), the said arm being provided with a gear-segment 14 that engages
with the segment-gear 7. It is provided also with a curved spur or projection 15,
the convex face of which receives the pressure of one end of the flat spring 16,
the opposite end of the latter being secured to the disk 6, as shown most clearly
in Figure 3. 17 is a movable or yielding arm, which in the drawing is shown
as consisting of a flat spring, it being connected at one end thereof to the case 1,
as by means of a screw 18 (see Figure 1). At or near its mid-length, the said
arm 17 rests against the top of the cam 9, and its free end enters an inclined or
spirally formed slot 19 in the hub 20, which latter is pivoted on the interior of the
case, as by means of the screw 21 (Figure 1). At 22 is an index or pointer which
is affixed to the hub 20, and at 23 is a graduated scale adjacent to the free
extremity of the said index or pointer. The inwardly extending portion of the
arm 12 is enlarged or weighted, as shown. Normally the spring 16 acts to hold
the arm 12 in the position in which it is shown in Figure 3, which corresponds
with the zero position of the index or pointer 22 that is shown in Figure 2.
the spindle 5 and disk 6 are rotated, the weighted portion of the arm 12 is urged
outwardly from the axis of rotation by the centrifugal force which is generated
in consequence of the said rotation, the tendency of the free end thereof to move
outward being opposed, however, by the action of the spring 16 upon the arm 15.
As the arm 12 swings outward, its gear-segment 14 rotates the segment-gear 7
relatively to the disk 6 and spindle 5, thereby causing a rotative movement of
the cam 8 relatively to the cam 9. The action of the cam 8 against the cam 9
causes the latter to move in the direction of the length of the rod or spindle 5,
thereby pushing upward the arm 17. The movement of the free end of the said
arm 17 in the inclined or spiral slot 19 of the hub 20 causes
the said hub to turn upon the pivotal screw 21, and swings the
index or pointer 22,
the extent of the movement of the said
index or pointer being indicated by the graduations of the scale 23. The
spring 16 causes the arm 12 and segment-gear 7 with its cam 8 to return toward
their normal positions as the speed of rotation slackens, while the resiliency of
the arm 17 acts to hold cam 9 pressed against cam 8 and to return the index or
pointer 22 toward its normal position at the zero end of the scale 23. In the
normal position of the parts shown in Figure 3, the free end of the spring 16
acts upon the inner portion of the convexly curved surface of the spur or pro-
jection 15 of arm 12. As the arm 12 swings outward under the influence of centri-
fugal force, this movement of the said arm brings successively into contact with
the springs 16 the portions of the curved surface of the spur or projection 15
which are farther and farther removed from the pivotal point of the arm 12, and
nearer and nearer to the fixed point of the spring 16. Thus the spring 16
becomes more and more effective in its action upon the spur or projection 15,
partly because of the decreased leverage which is secured in the manner just
stated, and partly because the said spring becomes in effect shorter and shorter
and hence opposes an increasing resistance to the movement of armi 12. In
this way, as the weighted inner or free end of arm 12 is caused to pass farther
and farther away from the axis of rotation in the manner hereinabove described,
and as the centrifugal force is increased in consequence of the said movement
away from the axis of rotation, the resistance offered by the spring to the out-

page_text: ward. movement of the arm is correspondingly increased by transferring the
point of contact between the convex surface of the tail or projection farther from
the axis of the weighted arm and nearer to the fixed point of the spring 16.
Thereby I am enabled to utilize a scale 23 which has its graduations at uniform
distances apart, and to obtain a wide ratio or capacity for the device. The curved
surface of the tail or projection of the weighted arm I term, for convenience of
designation, a compensating cam. By means of the said compensating cam, I
secure the differential spring action which I have explained above.
In the modification which is represented in Figures 4 and 5, the upper end
of the rod or spindle 5 is prolonged somewhat, and is reduced in diameter, the
reduced prolongation passing through a slot 51 which is made in the yielding
arm 17, as shown in Figure 5. The slot 51 is elongated in the direction of the
length of the said arm, so as to permit the movements of the parts to take place
without obstruction. This construction may be adopted if though fit, to guard
against any lateral displacement of the arm 17 and upper cam.
.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is:
1. A speed-indicator comprising, in combination, a rotating spindle, a pivoted
weighted arm rotating in unison therewith and provided with a compensating
cam, a spring also rotating with the said spindle and acting against the said
cam, an index or pointer, and means to actuate the said index or pointer from
the said weighted arm, substantially as described.
2. A speed-indicator comprising, in combination, a rotating spindle, a weighted
arm pivotally carried by the said spindle and adapted to swing away from the
axis of rotation under the influence of centrifugal force, the said weighted arm
having a toothed rack and a compensating cam, a spring also rotating with the
spindle and bearing against the said cam, the loose pinion engaged by the said
rack and provided with the cam at the side thereof, the movable piece in contact
with the said cam and turning in unison with the spindle, with capacity to move
endwise thereof, an index, and means to actuate the same from the said movable
piece, all substantially as described.
3. A speed-indicator comprising, in combination, a rotating spindle, a weight
rotating in unison with the said spindle and adapted to move away from the axis
of rotation under the influence of centrifugal force, means to oppose the outward
movement and return the weight toward the axis of rotation, an arm, and means
intermediate the same and the weight to move the arm, the hub provided with the
inclined cam-slot which is engaged by the said arm, and the index connected
with the said hub, all substantially as described.
4. A speed-indicator comprising, in combination, a rotating spindle, a weight
supported by the said spindle and adapted to move away from the axis of rotation
under the influence of centrifugal force, a spring tending to move the said weight
toward the axis of rotation, a cam mounted concentrically with the said spindle,
means to operate the said cam from the said weight, a movable piece in contact
with the said cam and turning in unison with the spindle, with capacity to move
endwise thereof, an arm operated by the said movable piece, the hub provided
with the inclined cam-slot, which is engaged by the said arm, and an index con-
nected with the said hub, substantially as described.
5. A speed-indicator comprising, in combination, a rotating spindle, a weighted
arm carried pivotally by the said spindle and adapted to swing away from the
axis of rotation under the influence of centrifugal force, the said weighted arm
having a compensating cam, a spring also rotating with the spindle and bearing
against the said compensating cam, a cam mounted concentrically with the said
spindle, means to operate the said cam from the said weighted arm, a movable
piece in contact with the said cam and turning in unison with the spindle, with
capacity to move endwise thereof, an arm operated by the said movable piece,

page_text: the hub provided with the inclined cam-slot which is engaged by the projection
of the said arm, and an index connected with the said hub, all substantially as
described.
6. A speed-indicator comprising, in combination, a rotating spindle, a weighted
arm pivotally carried by the said spindle and adapted to swing away from the axis
of rotation under the influence of centrifugal force, the said weighted arm having
a toothed rack and a compensating cam, a spring also rotating with the spindle
and bearing against the said cam, the loose pinion engaged with the said rack
and provided with a cam, a movable piece in contact with the said cam and turn-
ing in unison with the spindle, with capacity to move endwise thereof, an arm
operated by the said movable piece, the hub provided with the inclined cam-slot
which is engaged by the projection of the said arm, and the index connected
with the said hub, all substantially as described.
7. In a speed-indicating device actuated by centrifugal force, a weight capable
of lateral movement from the axis of rotation, and a restraining spring whose
effective length
or tension is changed in proportion to the movement of the weight
from the axis of rotation, substantially as described.
8. In a speed-indicator, the combination of a weighted lever moving in a
circular path from the axis of rotation, and remaining in the same plane of
rotation, said lever carrying a segment of a gear, an index-finger moved over a
scale by the action of said weighted lever, and a restraining spring whose effective
length or tension is changed in proportion to the movement of the weighted
lever, substantially as described.
Dated his 00d do of T
1907
ALBERT LYMAN PARCELLE.
Haseltine, Lake & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.