U.S. patent number 3,673,793 [Application Number 05/118,889] was granted by the patent office on 1972-07-04 for direct charge-rate indicator.
Invention is credited to George A. Barnard, III.
United States Patent |
3,673,793 |
Barnard, III |
July 4, 1972 |
DIRECT CHARGE-RATE INDICATOR
Abstract
A device for indicating the cost of an operation having at least
one charge-rate applicable thereto comprises a compound dial
including fixed and movable dial surface which have inscribed
thereon logarithmic time and charge scales. A clutch arrangement is
provided to allow pre-setting of an applicable charge-rate by
manipulation of the dial surfaces. To effect multiplication of that
charge-rate by the operation's elapsed time, a timer is included
having start and stop controls which provides an output movement
proportional to elapsed time. A drive linkage couples this output
movement to the movable dial surface so that relative movement
between the scales proceeds logarithmically with respect to elapsed
time. An embodiment of the device for use as a telephone
long-distance call charge indicator is described, including various
embodiments of the compound dial and drive linkage therefor.
Inventors: |
Barnard, III; George A.
(Bellevue, WA) |
Family
ID: |
22381359 |
Appl.
No.: |
05/118,889 |
Filed: |
February 25, 1971 |
Current U.S.
Class: |
235/61R; 235/61C;
379/114.01 |
Current CPC
Class: |
H04M
15/04 (20130101) |
Current International
Class: |
H04M
15/04 (20060101); G04b 047/00 (); G07c
001/00 () |
Field of
Search: |
;179/7.1R ;235/61C
;58/145K,152T,141 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wilkinson; Richard B.
Assistant Examiner: Simmons; Edith C.
Claims
What is claimed is:
1. An apparatus for indicating the cost of an operation having an
applicable charge-rate comprising:
a. a timer for providing an output movement related to the
operation's elapsed time,
b. first and second dials having placed thereon logarithmic time
and charge scales, respectively,
c. means for adjusting the relative positions of said time and
charge scales by displacement of said first and second dials,
d. an index aligned with an increment of said time scale,
e. drive means for providing relative logarithmic movement between
said charge scale on said second dial and said index in response to
said output movement.
2. An apparatus as recited in claim 1, wherein said drive means
includes means providing a time delay between the initiation of
said output movement and the initiation of said relative
movement.
3. An apparatus as recited in claim 1, wherein said timer provides
an output movement which varies linearly with respect to elapsed
time, and wherein said drive means includes means for translating
said linear output movement into an output movement which varies
logarithmically with elapsed time.
4. An apparatus as recited in claim 1, wherein said timer provides
an output movement which varies logarithmically with elapsed
time.
5. An apparatus as recited in claim 1, wherein said timer includes
a shaft rotatable to provide said output movement, and wherein said
drive means comprises a second shaft, means supporting said second
shaft for rotation, linkage means coupling said timer shaft to said
second shaft, and wherein said adjusting means comprises a clutch
means supporting one of said dials for rotation with said second
shaft.
6. An apparatus as recited in claim 5, wherein said timer shaft
rotates linearly with elapsed time, and wherein said linkage means
includes a disc rotatable with said timer shaft, said disc defining
therein a spiral slot, a pinion gear rotatable with said second
shaft, a rack, means supporting said rack for movement with said
pinion gear, and said rack having a pin ridable in said spiral
slot.
7. An apparatus as recited in claim 1, wherein said timer includes
a shaft rotatable to provide said output movement, and wherein said
drive means comprises a lever arm, means supporting said lever arm
for pivotal movement, a disc rotatable with said timer shaft, said
disc defining therein a spiral slot, and wherein said lever arm has
at one end thereof a pin ridable in said spiral slot, said lever
arm supporting at another end thereof said index.
8. A telephone long-distance call charge indicator including:
a. a housing,
b. a timer supported by said housing and providing an output
rotation of a shaft thereof which varies with time,
c. a disc means supported by said timer shaft within said housing
which defines at least one notch therein,
d. a first logarithmic scale inscribed on said housing whose
markings correspond to time units,
e. a dial having inscribed thereon a second logarithmic scale whose
markings correspond to charge units,
f. a dial shaft supported by said housing for rotation,
g. clutch means supporting said dial on said dial shaft so that
said first and second scales are in register, said clutch allowing
the relative displacement of said dial with respect to said dial
shaft,
h. a linkage means coupling said dial shaft to said timer
shaft,
i. a latching means supported by said housing for selective
engagement with said notch for selective initiation of rotation of
said timer shaft, and
j. means supported by said housing for selective termination of
rotation of said timer shaft.
9. An indicator as recited in claim 8, wherein said timer shaft
rotates linearly with time, and wherein said disc means defines a
spiral slot, said linkage means further including a pinion gear
rotatable with said dial shaft, a rack, means supporting said rack
from said housing for movement with said pinion gear, and wherein
said rack includes a pin ridable in said spiral slot.
10. An indicator as recited in claim 9, wherein said disc further
defines a circular slot adjacent to and continuous with said spiral
slot, the relative positions of said notch and said circular slot
in said disc being chosen so as to provide a time delay between the
initiation of rotation of said timer shaft and the initiation of
rotation of said dial shaft.
Description
FIELD OF THE INVENTION
This invention generally relates to charge-rate indicators, and,
more particularly, to devices for providing a direct indication of
the cost of an operation while in progress.
BACKGROUND OF THE INVENTION
For many operations, the cost thereof can be determined from a
predetermined charge-rate. The charge-rate is expressed in terms of
a certain number of monetary units, such as cents, per a certain
number of time units, such as minutes. The cost of the operation
then equals the product of the operation's elapsed time and the
applicable charge-rate.
One example of such an operation is a telephone long-distance call.
In the United States, a distinct charge-rate schedule is applicable
for each point-to-point long-distance call. The charge-rate
schedule includes a basic or fixed charge for the first 3 minutes
of the call's elapsed time, plus a charge-rate applicable for
subsequent elapsed time of the call.
Because of the large expense generally involved in making these
calls, it is desirable to have a direct and instantaneous
indication to the person making the call of the cost thereof. Since
the charge-rate schedule is complex, it is not feasible for the
telephone user to keep a running account of the cost of the call
while in progress.
There have been proposed devices which indicate to the telephone
user the accumulated or total cost of a long-distance telephone
call. However, these devices have not found widespread acceptance,
as they are expensive to construct, clumsy to use, and inflexible
in that their mechanisms are not readily adaptable to different
charge-rate schedules.
Therefore, it is an object of this invention to provide an
apparatus for directly indicating the cost of an operation having a
charge-rate schedule, while in progress.
It is a further object of this invention to provide an apparatus
for directly indicating the instantaneous and total cost of a
long-distance telephone call.
It is yet another object of this invention to provide a telephone
long-distance call charge indicator which is self-contained, simple
of construction, and independent of existing telephone
equipment.
It is a further object of this invention to provide a telephone
long-distance call charge indicator which calculates the cost of
the call, while in progress, from an applicable charge-rate
schedule and which allows the user to pre-set any charge-rate
schedule therein.
SUMMARY OF THE INVENTION
These objects and others, which will be realized through
consideration of the following portion of the specification, are
achieved, briefly, by a controllable timer providing an output
movement which is related to elapsed time of the operation, a
compound dial including first and second relatively movable dial
surfaces having inscribed thereon first and second, logarithmic
scales representing monetary units and units of time, respectively,
and a drive linkage coupling said output movement to one of said
surfaces so as to effect relative movement therebetween at a rate
proportional to the logarithmic rate of change of said scales.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention can perhaps best be understood by reference to the
following portions of the specification, taken in conjunction with
the accompanying drawings, in which:
FIG. 1 is an isometric view showing an embodiment of the invention
for use as a telephone long-distance call charge indicator;
FIGS. 2, 3, 4 and 5 are views illustrating the operation of the
indicator of FIG. 1;
FIGS. 6 and 7 are exploded orthographic and section views,
respectively, of the indicator of FIG. 1;
FIG. 8 is an exploded orthographic view of a telephone
long-distance call charge indicator including a timer providing a
logarithmically varying output movement, and,
FIGS. 9 and 10 are partial schematic views of yet another
embodiment of the indicator.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With particular reference now to FIG. 1, a telephone long-distance
call charge indicator comprises a housing including a first housing
portion 10 having a front surface 10a which defines first and
second, arcuate windows 12, 14. Housing portion 10 also has a
generally lateral surface 10b which defines an apertured recess 18
through which projects the knurled edge of a first rotatable dial
20.
The indicator also includes a second housing portion 22 having a
front surface 22a which defines an arcuate window 24. Housing
portion 22 has a generally lateral surface 22b which defines an
apertured recess 26 through which projects the knurled edge of a
second rotatable dial surface 28. Also projecting through surface
22b are push buttons 30 and 32 which are used to initiate and
terminate the operation of the indicator.
A timer 34 is affixed to the rear of housing portion 22 and may be
either mechanically or electrically powered to provide the desired
output movement.
To fully understand the operation of the indicator, a discussion
must be made of the types of charge-rate schedules for which it is
applicable. In the United States, the basic or fixed charge is
levied whenever the elapsed time of the call is equal to or less
than an initial amount of time. For example, the basic charge may
equal X cents for the first 3 minutes of the call. After the
initial time period has elapsed, the charge is computed from the
product of an applicable charge-rate and the elapsed time of the
call, subsequent to the initial period. For example, the
charge-rate may equal Y cents for every 3 minutes thereafter. In
all cases, the elapsed time of the call is measured from the time
when the connection is made between the calling and called parties,
to the time when one of these parties places his telephone receiver
on-hook.
The charge-rate schedule applicable to a specific long-distance
call can be ascertained from any telephone company if the points
between which communication is desired are known, as the tariffs
including these charge-rate schedules are matters of public
record.
Once the particular charge-rate schedule applicable to the call has
been determined, the schedule may be pre-set into the indicator in
the following manner. With particular reference now to FIG. 2, a
portion of a first charge scale C1 is viewable through window 24.
Scale C1 includes a plurality of charge markings and the wording
"Does Not Apply" which may be brought individually into
correspondence with window 24 by rotation of the dial 28. The
portion of scale C1 that can be viewed through window 24 serves as
a reminder of the basic charge for the call. A fixed index 25 is
located on surface 22a adjacent window 24 so as to aid the user in
setting the basic charge.
The user must then pre-set the applicable charge-rate. The window
12 is closed from view by a shutter surface S in position S1. As
the window 14 is open, first and second scales R and T are viewable
therethrough. In a preferred embodiment, scale R is inscribed on
dial 20 and movable therewith, and scale T is inscribed on surface
22a. Scale R includes a plurality of charge markings. Scale T
includes a plurality of time markings. The charge-rate is pre-set
by rotating dial surface 20 so that the marking appearing on scale
R corresponding to the cost unit of the charge-rate is opposite the
marking appearing on scale T corresponding to the time unit
thereof.
For example, the charge-rate schedule for a particular
long-distance call may be 40 cents for the first 3 minutes, and 20
cents for every 3 minutes thereafter. With reference now to FIG. 3,
the user has rotated dial 28 so that the marking "40.cent." on
scale C1 appears opposite the index 25, and has rotated dial 20 so
that the marking "20.cent." on scale R is opposite the marking "3"
on scale T.
When the connection is made and the call begins, the user depresses
push button 30. Thereafter, the indicator continues to appear as
shown in FIG. 3 until the initial 3-minute period has elapsed. At
the end of the initial period, the indicator appears as shown in
FIG. 4. The shutter surface S has been removed from position S1
behind window 12, thus revealing a portion of second charge scale
C2 therethrough, and the window 14 has been closed by shutter
surface S in a position S2. Scale C2 includes a plurality of charge
markings similar to those of scale R and is read by comparison with
a fixed index 29 on surface 10a. At this time, the user may
determine the total charge for the call in progress by taking the
sum of the charges appearing in windows 24 and 12. In FIG. 4, the
untaxed charge for the call in progress is 46 cents.
The scale C2 is inscribed on a dial which does not begin to rotate
until the initial time period plus an amount of time equal to one
increment of the scale T has elapsed. Since scale T is inscribed in
minutes, scale C2 in FIG. 4 remains stationary throughout the 4th
minute of the telephone call. At the end of the 4th minute, the
dial on which scale C2 is inscribed begins to rotate at a rate
related to the rate of change of the markings thereon. The user may
then continuously monitor the charge accruing from his telephone
call by reading the scale C2. He may also determine the total
charge by summing the readings of scales C1 and C2.
At the termination of the call, the user depresses push button 32
to stop the rotation of the dial on which scale C2 is inscribed.
The indicator then appears as shown in FIG. 5. The call has been
terminated after an elapsed time of 15 minutes, and the total
untaxed charge is "80.cent." plus "40.cent.," or $1.20.
In the United States, long-distance telephone calls are subjected
to an excise tax expressed in terms of a percentage. The indicator
can provide a direct indication of the taxed charge for the
telephone call, if the user pre-sets a basic charge and charge-rate
which are equal to the untaxed basic charge and charge-rate,
multiplied by the excise tax percentage.
If the applicable charge-rate schedule only consists of a
charge-rate, dial 28 is rotated so that the "Does Not Apply"
marking of scale C1 appears in window 24. After pre-setting the
applicable charge-rate by manipulation of dial 20, the user
depresses push button 30 at the initiation of the call. The surface
S is then moved from position S1 to position S2. Thereafter, the
dial having scale C2 inscribed thereon begins to rotate after one
time increment has elapsed. In other words, the operation of the
indicator is identical to that previously described, with the
exception that the time delay between the depression of push button
30 and the rotation of scale C2 does not include a component equal
to the initial time period.
An embodiment of the indicator for providing this operation is seen
in FIGS. 6 and 7.
The timer 34 provides an output movement which is proportional to
time. More specifically, timer 34 is wound by rotation of key 35 so
that a shaft 40 thereof rotates in a clockwise direction with
respect to time. Shaft 40 is rotatably journaled in a rear surface
22c of housing portion 22, passes through a braking drum 42, and is
terminated in a disc 44. Both drum 42 and disc 44 are attached
rigidly to shaft 40 and maintained in spaced relation thereon by
spacers 40a, 40b.
The time-related rotation of shaft 40 accordingly appears as a
clockwise rotation of disc 44. A linkage means is provided between
disc 44 and the movable dial so as to convert the linear,
time-related movement of disc 44 into a movement of the dial which
varies with respect to time at a rate corresponding to the rate of
charge of the scale inscribed thereon. For multiplication to occur,
this rate of change must be logarithmic such that the rate of
rotation of dial 20 decreases with clockwise rotation of shaft
40.
In detail, disc 44 defines a spiral slot 46. A rack 50 is supported
within housing portion 22 by a guide means not illustrated for
vertical, translative movement and includes a pin 48 at one end
thereof which rides in slot 46. A plurality of teeth on rack 50
engage corresponding teeth on a pinion gear 52 which is mounted at
one end of a rotatable shaft 54, rotatably journaled in housing
walls 10a and 22a. The portion of shaft 54 within housing portion
22 has a return spring 56 attached thereto and loosely supports
dial 28.
The portion of shaft 54 within housing portion 10 supports movable
dial 20 which is rotatable with shaft 54 but whose relative
position is adjustable by means of a friction clutch arrangement
including first and second washers 68a, 68b, a spring spider 68c,
and a spacer 52a. A movable, transparent shutter 58 is supported
for translative movement within housing portion 10 by a pair of
guides 60, 62 affixed thereto. Shutter 58 includes a longitudinal
aperture 64 through which passes shaft 54 so that shutter 58 is
movable independent of shaft 54. A tension spring 66 maintains
shutter 58 in a normally retracted position.
The scale C1 is inscribed on movable dial 28 and viewable through
window 24 as heretofore described. The scale T is inscribed on
surface 22a of housing portion 22. The movable dial 20 is
preferably composed of a transparent material and includes scales R
and C2 inscribed thereon. In assembly, scales R and C2 are directly
viewable through transparent shutter 58 and windows 14 and 12,
respectively, and scale T is viewable in register with scale R
through window 14, shutter 58 and transparent dial 20. Shutter
positions S1 and S2 are both provided by an opaque shutter surface
S on shutter 58.
The spiral slot 46 is configured to (a) provide the necessary
linear-logarithmic translation between shafts 40 and 54, and (b)
provide a time delay between the initiation of operation of the
indicator and initiation of revolution of dial 20 on which scale C2
is inscribed. To accomplish these functions, slot 46 is divided
into portions 46a and 46b. Portion 46a is circular and the length
thereof determines the duration of the initial period, plus one
increment of the time scale T. Portion 46b is a spiral whose length
determines the maximum duration of the remainder of the period of
operation and which is configured to provide, in conjunction with
rack 50 and pinion 52, the required linear-logarithmic
translation.
The periphery of disc 44 has a plurality of notches 44a, 44b and a
finger 44c which allow control of the starting point of operation
in conjunction with push button 30 and an associated latch-spring
arrangement.
In detail, push button 30 is attached at one end to the latch 70
which is pivotable about a pivot 78 secured to the housing portion
22. Latch 70 includes a first finger 70a which is adapted to coact
with notches 44a and 44b. A second finger 70b thereof is adapted to
coact with a finger 72b of a second latch 72 which is slidable in a
channel 73 also secured to the housing portion 22. A finger 72a is
pivoted on latch 72 and has rotatable thereon a roller 80 which is
adapted to coact with finger 44c of disc 44. A compression spring
76 within channel 73 normally forces latch 72 against latch 70, a
compression spring 74 tends to force finger 70a of latch 70 into
engagement with the periphery of disc 44, and a leaf spring 75
normally forces finger 72b against a shoulder 72' of latch 72.
The latch-spring arrangement associated with push button 30 is
shown in a running position in FIG. 6. When the indicator is to be
set for operation, the user winds timing means 34 by key 35 so that
shaft 40 rotates in a counter-clockwise direction, as viewed in
FIG. 6. During this rotation, finger 44c first comes into
engagement with the pivoted roller 80. Further rotation of disc 44
in a counter-clockwise direction then pushes latch 72 back along
channel 73, against the force of compression spring 76, so that
finger 72b thereof is released from engagement with finger 70b of
latch 70. At this time, compression spring 74 forces finger 70a
against the periphery of disc 44.
Upon further counter-clockwise rotation of disc 44, finger 70a
falls into and rides out of notch 44b, then falls into and rides
out of notch 44a. The amount of counter-clockwise rotation is
limited by a pin 82 affixed to disc 44 which engages, at a degree
of rotation past the coincidence of finger 70a and notch 44a, a
projection 84 affixed to housing portion 22. When the key 35 is
then released, timer 35 begins to rotate shaft 40 in a clockwise
direction. However, the rotation is stopped when finger 70a again
drops into notch 44a. At this time, the indicator is ready for
operation.
When the long-distance call connection is made, the user depresses
push button 30. This action rotates latch 70 about pivot 78 so as
to raise finger 70a out of notch 44a. Thereafter, the timer rotates
disc 44. At some point of depression of push button 30, finger 70b
slips under finger 72b and accordingly latch 70 is maintained in
the position shown in FIG. 6 by latch 72 and compression spring
76.
The relative positions of slot portion 46a and notches 44a and 44b
are chosen so that when finger 70a is resting in notch 44a, pin 48
of rack 50 is at a point some distance from the extreme right edge
of slot 46a. Similarly, when finger 70a is resting in notch 44b,
pin 48 is at a point corresponding to 1 minute's rotation of shaft
40 from the junction of slot portions 46a and 46b.
Because slot portion 46a is circular, that is, the radius thereof
with respect to shaft 40 does not change throughout its length, the
initial rotation of disc 44 when pin 48 is in a slot portion 46a
produces no corresponding movement of rack 50.
If the charge-rate schedule includes a basic charge, accordingly,
the disc 44 should be rotated upon winding of timer 34 so that
finger 70a comes to rest in notch 44a. Thereafter, rotation of
shaft 54, and thus of the scales on dial 20, occurs only after the
initial 3-minute period has elapsed, plus one minute. If the
charge-rate schedule includes only a charge-rate, the disc 44
should be rotated upon winding of timer 34 so that finger 70a comes
to rest in notch 44b. Thereafter, the pin 48 is in the slot portion
46 only for 1 minute's rotation of shaft 40.
As disc 44 continues to rotate, pin 48 enters the slot portion 46b.
Accordingly, further rotation of disc 44 moves rack 50 in a
downward direction. The locus of slot portion 46b with respect to
shaft 40 is chosen so that rack 50 is moved downwardly at a
logarithmic rate. The movement of rack 50 is transmitted, via
pinion gear 52, shaft 54 and clutch 68, to movable dial 20.
As previously described, the user will have turned movable dial 20
so as to pre-set the applicable charge-rate. It can be noted from
FIG. 6 that scale C2 is identical to scale R. Accordingly, rotation
of dial 20 provides a direct indication of the charge attributable
to the charge-rate, by comparison of the markings of scale C2
against index 29.
The shutter 58 is operable in the following manner. When the timer
34 is wound so that finger 70a engages either notch 44a or 44b, a
pin 86 on disc 44 engages first end 88a of an arm 88 which is
pivotable about a pivot 90 secured to housing portion 22. A second
end 88b of arm 88 rides in a corresponding aperture in shutter 58.
Accordingly, when pin 86 depresses end 88a, as best seen in FIG. 7,
end 88b is raised to move shutter 58 upwardly against the force of
tension spring 66 so that shutter surface S is in the position S1.
When disc 44 has rotated so that pin 48 has traversed the length of
slot portion 46a corresponding to the initial time period, pin 86
disengages end 88a so as to allow shutter 58 to return to its
normally retracted position such that shutter portion S is in
position S2.
To allow the linkage including rack 50 and disc 44 to operate
smoothly without binding, the pin 48 must be slightly less in
diameter than the width of slot 46. Spring 56 is needed to maintain
one edge of pin 48 in engagement with the only one edge of slot 46
to prevent changes in register between shafts 54 and 40.
The purpose of finger 72a is to allow finger 44c to pass latch 72
without disengagement of latch 70 as the disc 44 rotates during the
call. In detail, the front edge of finger 44c engages roller 80,
and rotates finger 72a against the force of spring 73 until
clear.
Disc 44 and dial 20 continue to rotate for the duration of the
telephone call. When the call is terminated, the user depresses
push button 32 so as to bring a braking shoe 32a attached thereto
into contact with braking drum 42. If desired, push button 32 may
be maintained in the depressed position by a latch-spring
arrangement similar to that used for push button 30.
When the indicator is to be reset, the user brings braking shoe 32a
out of engagement with braking surface 42, then winds the timer 34.
The subsequent clockwise rotation of disc 44 resets the push button
30 upon engagement of finger 44c with roller 80 in a manner
identical to that previously described.
The embodiment of FIGS. 6 and 7 incorporates a linear-logarithmic
translation in its drive linkage because the majority of timers
useful therefore provide an output movement which is linearly
related to time. However, there are devices available whose output
movements are non-linearly related to time. In such a case, the
simplified embodiment of FIG. 8 may be used, with appropriate
modifications to the timer if needed. One such timer is shown in
the U.S. Pat. No. 2,610,683 to Beiser. This patent discloses an
interval timer which is adapted to count down a desired period of
elapsed time at an inverse logarithmic rate. The timer operation is
initiated by winding a knob at the front thereof in a clockwise
direction. The output movement then proceeds in a counter-clockwise
direction at the aforementioned inverse logarithmic rate.
With particular reference now to FIG. 8, the timer 135 provides an
output movement of a common shaft 154 having attached thereto a
disc 144 which is a mirror image of disc 44 in FIG. 6. Also
attached to and rotatable with shaft 154 are a movable dial 120 by
a clutch arrangement 168, and a winding knob 116. Because the
output movement of shaft 154 proceeds in a counter-clockwise
direction with elapsed time, and since the linear-logarithmic
translation takes place within timer 135, the relative positions of
disc 144, start push button 130, stop push button 132 latch-spring
arrangement 131 for push button 130, notches 144a, 144b, finger
144c, pin 182 and pin 184 are all reversed with respect to the
corresponding elements 44, 30, etc., in FIGS. 6 and 7. Otherwise,
the operation is identical.
If the device in the aforementioned Beiser patent is used, the
relative position of the spiral gears should be inverted to provide
an output movement of shaft 154 which has a true logarithmic
variation whose rate decreases with time. For further details,
reference should be made to that patent whose specification is
fully incorporated by reference herein.
In operation, the user sets the indicator in FIG. 8 by winding knob
116 in a clockwise direction, pre-sets the applicable charge-rate
schedule by appropriate manipulation of dials 128 and 120, and
initiates and terminates operation by sequentially depressing push
buttons 130 and 132.
Another embodiment of the indicator for use in providing a direct
indication of the cost of practically any operation having an
applicable charge-rate is seen in FIGS. 9 and 10. The indicator
includes a timer, not shown, which may be similar to timer 34 of
FIG. 6, and which provides an output movement of a shaft 240 having
attached thereto a disc 244. In most respects, disc 244 is
identical to disc 44 of FIG. 6 and thus may have associated
therewith appropriate latch-spring arrangements for starting and
stopping the rotation thereof. Disc 244 includes a slot 246
comprising a circular portion 246a and a modified logarithmic
spiral portion 246b. A pin 248 attached to one end of a lever arm
250 rides in slot 246. Lever arm 250, which is pivotable about a
pivot point 251, has attached to the other end thereof a cursor 252
which is movable past a curved dial 253. Dial 253 is shown in more
detail in FIG. 10 and comprises an inner, curved dial 262 which has
inscribed thereon a logarithmic scale T1 corresponding to scale T
in FIG. 6. An endless tape 254, of transparent material, is
supported from dial 262 by a plurality of rollers 260 and is
relatively movable therewith by first and second end rollers 256,
258 and an adjusting knob 256a. Inscribed on transparent tape 254
is a logarithmic scale R1 corresponding to scale R in FIG. 6.
In operation, the user pre-sets the applicable charge-rate by
manipulating knob 256a so that the marking on scale R1
corresponding to the cost unit of the charge-rate is opposite the
marking on scale T1 corresponding to the time unit thereof. Then,
the starting mechanism, including a push button if desired, is
activated. At some point in the elapsed time of the operation,
cursor 252 is moved relative to scale R1 by lever arm 250 to
directly indicate the cost of the operation in progress.
The portion 246b of slot 246 must provide movement of cursor 252
relative to scale R1 which is basically logarithmic but which is
modified to compensate for the curvature of dial 253.
It is thus evident to those skilled in the art that the indicator
of this invention has great versatility in providing a direct
indication of the cost of an operation having an applicable
charge-rate, while that operation is in progress, and for providing
a direct indication of the total charge for the operation when
completed. Although the invention has particular applicability to
telephone long-distance call charge indicators, it is to be clearly
understood by those skilled in the art that the invention is not
limited thereto, but rather is intended to be bounded only by the
appended claims.
* * * * *