Information
-
Patent Grant
-
6780078
-
Patent Number
6,780,078
-
Date Filed
Friday, November 1, 200222 years ago
-
Date Issued
Tuesday, August 24, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Banks; Derris H.
- Abdelwahed; Ali
Agents
-
CPC
-
US Classifications
Field of Search
US
- 446 175
- 446 410
- 446 454
- 446 467
-
International Classifications
-
Abstract
A toy assembly that includes a remotely controlled vehicle is disclosed. In one embodiment, the toy assembly includes a remote control that can be used to control a toy vehicle. In one embodiment, the remote control includes a chip with pre-recorded content stored thereon. In one embodiment, the remote control can be coupled to an audio amplifier that can generate audible outputs. In another embodiment, the remote control can be used in a hand-held configuration.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to a toy assembly, and more particularly, to a toy assembly with a remotely controlled vehicle.
Many conventional toy assemblies include toy vehicles that can be manipulated to generate different play situations and scenarios. Some conventional toy vehicles are remotely controllable by a user. Such conventional toy vehicles are limited in scope and features. Accordingly, children become bored quickly while using conventional toy vehicles.
A need exists for a new toy assembly that has several features that provide various play scenarios for a child.
SUMMARY OF THE INVENTION
In one embodiment, the toy assembly includes a remotely controlled vehicle. In another embodiment, the toy assembly includes a remote control that can be used to control a toy vehicle.
In one embodiment, a remote control includes a chip with pre-recorded audible content. In one embodiment, the remote control can be coupled to an audio amplifier that can generate audible outputs. In another embodiment, the remote control can be used in a hand-held configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a perspective view of an embodiment of a toy assembly according to the invention.
FIG. 2
is a perspective view of another embodiment of a toy assembly according to the invention.
FIG. 3
is a perspective view of another embodiment of a toy assembly according to the invention.
FIG. 4
is a perspective view of another embodiment of a toy assembly according to the invention.
FIG. 5
is a schematic view of an embodiment of a controller according to the invention.
FIG. 6
is a schematic view of an embodiment of an output device according to the invention.
FIG. 7
is a schematic view of an embodiment of a connector according to the invention.
FIG. 8
is a schematic view of an embodiment of a station according to the invention.
FIG. 9
is a perspective view of an embodiment of a station according to the invention.
FIG. 10
is a top view of the station of FIG.
9
.
FIG. 11
is a perspective view of an embodiment of a controller according to the invention.
FIG. 12
is a side view of the controller of FIG.
11
.
FIG. 13
is an end view of the controller of FIG.
11
.
FIG. 14
is a perspective view of a station and several controllers according to the invention.
FIG. 15
is a schematic side view of an embodiment of a vehicle according to the invention.
FIG. 16
is a perspective view of a track section according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
In one embodiment, the toy assembly includes a remotely controlled vehicle. In another embodiment, the toy assembly includes a remote control that can be used to control a toy vehicle.
In one embodiment, a remote control includes a chip with pre-recorded audible content. In one embodiment, the remote control can be coupled to an audio amplifier that can generate audible outputs. In another embodiment, the remote control can be used in a hand-held configuration.
A perspective schematic view of an embodiment of a toy assembly according to the invention is illustrated in FIG.
1
. In this embodiment, the toy assembly
10
includes a track
12
. The track
12
can include any number of individual track sections, i.e. sections
20
and
22
, that can be coupled together in various combinations to form a continuous path on which a toy vehicle can travel. One type of track connection that can be used to couple track sections is disclosed in U.S. patent application Ser. No. 10/285,698, entitled “Toy Track and Method of Assembling and Disassembling the Same,” filed Nov. 1, 2002, the disclosure of which is incorporated by reference herein.
The toy assembly
10
includes several objects related to the environment of the toy assembly
10
. For example, the toy assembly
10
can include a warning light structure
14
, a gate crossing
16
, and a ramp
18
. These and other objects can be any shape or configuration and can be formed of plastic. The track
12
includes a bridge
24
and bridge ramps
26
and
28
coupled to the bridge
24
.
The toy assembly
10
can include any number of interactive work sites or structures that enhance the play options of the toy assembly
10
. In various embodiments, any combination of sites and/or structures can be used. In the illustrated embodiment, the toy assembly
10
includes a coal mine work site
30
. This work site
30
includes a bucket
32
that slides up and down to deliver a ball
48
to a hopper
36
. The hopper
36
is configured to receive the ball
48
and deliver the ball
48
to a shaft
42
. The shaft
42
is configured to receive the ball
48
and deliver it to a vehicle located below the shaft
42
.
The toy assembly
10
includes a gantry work site
50
. This work site
50
includes a frame
52
that supports a horizontal boom
54
. A claw
56
is slidably coupled to and movable along the boom
54
. The claw
56
can be manipulated to pick up a crate
58
or other object. This work site
50
can be located next to any straight piece or curved piece of track by engaging a finger (not shown) on the frame
52
with a groove (not shown) on the track
12
.
The toy assembly
10
includes a pipe works work site
60
. This work site
60
includes a pipe building
62
that delivers pipes to the front side
66
of the building
62
or to the back side
68
of the building
62
. A knob
64
is coupled to the building
62
. The knob
64
can be turned to deliver pipes to the front of the building
62
by turning the knob
64
counter-clockwise and to the rear of the building
62
by turning the knob
64
clockwise.
A vehicle can be placed in the front of the building
62
to receive pipes. In one embodiment, the work site
60
includes a rear ramp
69
on which a vehicle can be positioned to receive pipes from the building
62
. In one embodiment, the building
62
includes a smoke stack
65
from which a puff of smoke is produced when the knob
64
is turned. This site
60
can be disposed at any location along the track.
The toy assembly
10
includes several vehicles that can be moved along the track
12
. One vehicle
90
resembles a train and can be remotely controlled. The train
90
is a self-powered vehicle that can pull several other vehicles
92
.
The toy assembly
10
includes a controller or remote control
70
. The controller
70
can be used to control a vehicle of the toy assembly
10
. In this embodiment, the controller
70
is used to control the train
90
via infrared signals transmitted from the controller
70
to the train
90
.
In this embodiment, the controller
70
includes a body
72
and an actuator
74
that is movable relative to the body
72
. Based on the movement of the actuator
74
, the controller
70
sends the appropriate signals to the train
90
to control the motion thereof. In alternative embodiments, the controller
70
can have any shape or configuration.
The toy assembly
10
also includes an output unit or station
80
that has a base
82
and a docking area or port
84
. As illustrated in
FIG. 1
, the controller
70
can be coupled or docked to the station
80
. As discussed in detail below, the station
80
includes an output generating system that plays audible outputs when a controller is coupled to the port
84
.
Another embodiment of a toy assembly according to the invention is illustrated in FIG.
2
. In this embodiment, the toy assembly
100
includes a track
102
and several articles
104
and work sites
106
,
108
, and
110
that can be located proximate to the track
102
. Articles
104
and work sites
106
,
108
and
110
are intended to be illustrative only. In alternative embodiments, any number and types of articles and work sites can be utilized with the track
102
.
Toy assembly
100
includes several vehicles, including an engine
112
that can be remotely controlled. The other vehicles can include a coal car
114
, a pipe car
116
, a crate car
118
, and a caboose
120
.
In this embodiment, toy assembly
100
includes a station
130
and a controller
140
. The station
130
includes a base
132
and a docking area (not shown). The controller
140
includes a housing
142
and an actuator
144
that can be manipulated to control the engine
112
.
Another embodiment of a toy assembly according to the invention is illustrated in FIG.
3
. In this embodiment, the toy assembly
200
includes a track
202
and several articles
204
and work sites
206
,
208
, and
210
that can be located proximate to the track
202
.
Toy assembly
200
includes several vehicles, including an engine
212
that can be remotely controlled. Some other vehicles can include a crate car
214
, a coal car
216
, a pipe car
218
, and a caboose
220
. Any number of vehicles can be provided.
In this embodiment, toy assembly
200
includes a station
230
. The station
230
includes a base
232
and a docking area
234
.
Toy assembly
200
includes several controllers, each of which is programmed to control a single remotely controllable vehicle. As illustrated in
FIG. 3
, controllers
240
,
250
and
260
can be coupled to a docking area
234
of the station
230
. In this embodiment, controller
240
is configured to control a construction vehicle
222
, controller
250
is configured to control a fire engine
224
, and controller
260
is configured to control the train engine
212
. Each of the controllers
240
,
250
and
260
includes a housing and an actuator
242
,
252
and
262
, respectively, that can be manipulated to control the particular vehicle.
Toy assembly
200
includes a construction site
270
that can be coupled to and form part of the track
202
. The construction site
270
includes a track portion
272
and a crane
274
with a claw
276
.
Another embodiment of a toy assembly according to the invention is illustrated in FIG.
4
. In this embodiment, the toy assembly
300
resembles a construction site. The toy assembly
300
includes a track
302
and ramps
304
and
306
coupled to the track
302
. The toy assembly
300
also includes a crane
308
that has a claw
310
that is configured to grip a ball
312
or other object. The ball
312
can be dropped into a chute
314
that leads to a bucket
316
.
Toy assembly
300
includes a toy vehicle
320
. In this embodiment, the toy vehicle
320
includes a body
321
with wheels
322
coupled thereto. The vehicle
320
includes a receiver
324
that is coupled to the vehicle body
321
. The receiver
324
is an infrared (IR) receiver that is configured to receive IR signals from a remote source. The vehicle
320
includes an LED (not shown) that is illuminated when the vehicle
320
receives instructions to move. After a conventional power down sequence, the LED is turned off to indicate that the vehicle
320
has powered down.
In this embodiment, toy assembly
300
includes a controller
330
. The controller
330
is illustrated in a hand-held or stand along configuration. The controller
330
includes a housing
332
with a slot
334
formed therein. The housing
332
includes an IR transmitter
336
located on one of its surfaces. The IR transmitter
336
transmits IR signals to the vehicle
320
. In alternative embodiments, the controller
330
can have more than one transmitter and each transmitter can be located at any location on the controller
330
.
The controller
330
includes an actuator
340
. The actuator
340
includes a shaft
342
with a grip portion
344
located at its upper end. The actuator
340
can be manipulated to close a switch in the housing
332
and send corresponding signals via the transmitter
336
to the vehicle
320
.
Schematic views of an embodiment of a controller according to the invention are illustrated in
FIGS. 5-7
. Controller
400
includes a control unit or processor
402
and an associated memory
404
. The processor and memory can be any conventional processor and memory in which audible outputs and programmed logic can be stored. Some of the audible outputs can include sound effects associated with particular vehicles.
The controller
400
includes an output device
408
that is connected to the processor
402
. The output device
408
can be any type of device that generates an output. In the illustrated embodiment, the output device
408
is an IR transmitter that transmits IR signals to a vehicle. In other embodiments, the output device can be a transmitter that transmits any type of signals, including radio frequency, electromagnetic, etc.
The controller
400
includes a power supply
410
that is connected to the processor
402
. In this embodiment, the power supply
410
is several batteries. In other embodiments, any other type of power supply can be used.
The controller
400
also includes an input device
406
. The input device
406
can be any device that receives an external signal or that can be manipulated to generate a signal that can be sent to the processor. In the illustrated embodiment, the input device
406
is a switch, and in particular, the input device
406
is a three position switch.
The controller
400
also includes an actuator
420
. The actuator
420
is coupled to the controller
400
for movement relative thereto. Actuator
420
is configured to engage the input device
406
so that an appropriate signal is generated and sent to the processor
402
. In the illustrated embodiment, the actuator
420
can be moved to place the switch in any one of its three positions.
The controller
400
also includes a connector
412
that is connected to the processor
402
. The connector
412
can be used to couple the controller
400
to another device that includes an output generating mechanism. For example, the connector
412
can be coupled to a corresponding connector on a device that includes a speaker through which audible outputs stored in memory
204
can be played, as discussed in detail below.
A schematic view of an embodiment of an output device according to the invention is illustrated in FIG.
6
. The output device
408
includes two emitters or transmitters
430
and
432
, each of which is configured to transmit a signal. The transmitters
430
and
432
are configured to transmit an IR signal. In alternative embodiments, the output device can include any number of emitters or transmitters.
A schematic view of an embodiment of a connector according to the invention is illustrated in FIG.
7
. The connector
412
includes two metallic or conductive contacts
440
and
442
. In an alternative embodiment, the connector can include any number of contacts. The function of the contacts is described below.
A schematic view of an embodiment of a station according to the invention is illustrated in FIG.
8
. The station
450
includes an output generating mechanism
452
. The output generating mechanism
452
includes conventional electrical components that are used to generate an audible output. In one embodiment, the output generating mechanism
452
includes a connector
454
and a transducer or speaker
456
. The connector
454
is configured to engage and be operatively coupled to the connector
412
on the controller
400
. When the connectors
412
and
454
contact each other, power is supplied from the controller
400
to the speaker
456
and the processor
402
selects an audible output, such as a sound effect for a particular vehicle, from the memory
404
. The selected audible output is then generated by the speaker
456
.
An embodiment of a station according to the invention is illustrated in
FIGS. 9 and 10
. In this embodiment, the station
500
includes a base
502
that has an upper surface
504
. Several walls
506
,
508
and
510
are disposed along the perimeter of the upper surface
504
to form an enclosure.
The station
500
includes several coupling or docking areas or ports
520
,
522
,
524
and
526
that are each configured to receive a controller therein. The docking areas
520
,
522
,
524
and
526
can be separated by a wall or other structure or alternatively, can be part of an open area as illustrated in FIG.
10
.
The station
500
includes several connectors or contacts associated with each of the ports. As illustrated, contacts
530
are associated with port
520
, contacts
532
are associated with port
522
, contacts
534
are associated with port
524
, and contacts
536
are associated with port
526
. In alternative embodiments, any number and type of contact can be used in each of the ports. Similarly, the contacts can be located on one of the walls of the station instead of or in addition to the upper surface of the base.
An embodiment of a controller according to the invention is illustrated in
FIGS. 11-13
. In this embodiment, the controller
600
includes a housing
602
with an upper surface
604
, a lower surface
606
, and a front surface
608
. In some embodiments, a plate
610
can be coupled to the upper surface
604
. The upper surface
604
and the plate
610
have a slot
612
formed therein.
The controller
600
includes an output device or transmitter
614
coupled to the housing
602
. In this embodiment, the transmitter
614
is configured to transmit IR signals to a vehicle. In an alternative embodiment, the controller
600
can have multiple transmitters spaced apart from each other.
In one embodiment, the controller
600
includes several contacts
616
and
618
on its lower surface
606
. The contacts
616
and
618
are metallic or conductive pieces of material that are coupled to the housing
602
. The contacts
616
and
618
are configured to engage any set of contacts on the station
500
. In alternative embodiments, the contacts can have any shape or configuration and the controller can include any number of contacts.
The controller
600
includes an actuator
620
that is movably coupled to the housing
602
. The actuator
620
includes a shaft
622
and a handle or grip
624
. As the actuator
620
is moved, the shaft
622
can travel along the slot
612
on the housing
602
.
As illustrated in
FIG. 12
, the actuator
620
can be positioned in several different positions relative to the housing
602
. The actuator
620
can be disposed in a first position
630
, a second position
632
, and a third position
634
. In one embodiment, the first position
630
corresponds to an off position, the second position
632
corresponds to a forward movement position, and the third position
634
corresponds to a forward movement and audible output position. In one embodiment, the positions
630
,
632
and
634
of the actuator
620
can be approximately 45°, 70° and 95°, respectively, from a horizontal plane that extends toward the front of the controller
620
.
When the actuator
620
is in its first position
630
, the controller
600
does not send a signal to the vehicle. When the actuator
620
is in its second position
632
or in its third position
634
, the controller
600
sends an intermittent IR signal to the vehicle instructing the vehicle to move forward. The signal is sent via an IR transmission in the form of packets of binary code. When the actuator
620
is in its third position
634
and the controller
600
is coupled to the station
500
, an audible output is generated from the station. Thus, audible outputs are generated by the station
500
only when a controller is coupled to the station
500
.
In the illustrated embodiment, the controller
600
includes a biasing element
623
, such as a spring, that biases the actuator
620
from its third position
634
to its second position
632
. Thus, when released, it naturally moves back to the second position. In other embodiments, the biasing element can be any structure that can bias the actuator
620
in a particular direction.
Referring to
FIG. 14
, several controllers are coupled to a station. Controllers
710
,
720
and
730
are coupled to the station
700
in a manner similar to that previously described. Controllers
710
,
720
and
730
are each configured to send control signals to a particular vehicle or object in a toy assembly. In one embodiment, each controller
710
,
720
and
730
is configured to transmit packets of binary code at different pulse rates. The pulse rates are based on a rate of commands per second. Each vehicle is likewise configured to receive a signal that is being transmitted at a particular pulse rate, and therefore, receive a signal from only one of the controllers.
Each of the controllers
710
,
720
and
730
includes an actuator that can be moved to different positions. When the actuator of any one of the controllers
710
,
720
and
730
is moved to its third position, as previously described, a corresponding audible output stored in the memory of the particular controller is output via the speaker in the station
700
and a forward motion signal is transmitted to the corresponding vehicle. The speaker in the station reduces the need to provide a speaker in each of the controllers in order to generate an audible output associated with a particular controller and vehicle.
An embodiment of a vehicle according to the invention is illustrated in FIG.
15
. In this embodiment, the vehicle
800
includes a body
802
with a top surface
803
, a front end
804
, and a rear end
806
. The vehicle
800
includes a connector
808
coupled to the rear end
806
of the body
802
. The connector
808
has an upwardly extending hook member
810
that can be engaged with a corresponding recess of another vehicle.
The vehicle
800
includes several wheels
812
and
814
are coupled to the body
802
. The wheels
812
and
814
can be driven by an internal drive mechanism (not shown). An exemplary drive mechanism that can be used is disclosed in co-pending U.S. patent application Ser. No. ______, entitled “Drive Mechanism for a Toy Vehicle and a Method of Using the Same,” filed Nov. 1, 2002 (Attorney Docket No. FSHR-063/00US), the disclosure of which is incorporated by reference herein.
In this embodiment, the vehicle
800
includes an LED
820
located proximate to its front end
804
and a receiver
822
disposed proximate to its upper surface
803
. The LED
820
indicates when the processor on the vehicle
800
has entered a power down mode. The vehicle
800
includes a reset switch (not shown) that can be pressed to activate the processor on the vehicle from its power down mode.
The receiver
822
can be enclosed by a cover
824
. In one embodiment, the receiver
822
is an IR receiver that is configured to receive IR signals from an external source.
In one embodiment, the wheels of the vehicle
800
include molded in friction strips that engage a support surface as the vehicle
800
moves. In another embodiment, the wheels of the vehicle
800
include ridges formed therein that enhance traction of the wheels along a support surface.
An embodiment of a track section according to the invention is illustrated in FIG.
16
. In this embodiment, the track section
900
includes a body portion
902
that has a ridge
904
that extends along the track section
900
. In alternative embodiments, the openings or recesses in the rail
904
can have any particular shape, configuration and frequency along the rail.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope thereof. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
Claims
- 1. A toy comprising:a housing, said housing including a body defining a coupling area and an output generating device; a toy vehicle; and a controller, said controller including a control unit having audible outputs stored therein, said controller being configured to provide instructions to said toy vehicle to move said toy vehicle and to be coupled to said housing at said coupling area, said controller being operable in a first configuration separate from said housing and in a second configuration coupled to said housing, said housing being configured to generate an audible output when said controller is coupled to said housing.
- 2. The toy of claim 1, said toy vehicle being a first toy vehicle and said controller being a first controller, said toy further comprising:a second toy vehicle; and a second controller, said second controller being configured to provide instructions to said second toy vehicle to move said second toy vehicle, said coupling area of said housing including a first port configured to receive said first controller and a second port configured to receive said second controller.
- 3. The toy of claim 2, said first controller including an outer surface and a contact disposed on said first controller outer surface, said second controller including an outer surface and a contact disposed on said second controller outer surface, said housing including a first contact and a second contact disposed thereon, said first contact being configured to be coupled to said first controller contact, and said second contact being configured to be coupled to said second controller contact.
- 4. The toy of claim 1, said controller including an outer surface and a pair of contacts disposed on said outer surface, said pair of contacts being connected to said control unit.
- 5. The toy of claim 1, said controller including an outer surface and a pair of contacts disposed on said outer surface, said pair of contacts on said controller being connected to said control unit, and said housing including a pair of contacts, said housing pair of contacts being connected to said output generating device.
- 6. The toy of claim 1, said controller including a body and an actuator coupled to said body, said actuator being selectively disposable in a plurality of positions with respect to said body.
- 7. The toy of claim 1, said controller including a body and an actuator coupled to said body, said actuator being selectively disposable in a plurality of positions with respect to said body, said plurality of positions including a first position corresponding to an off position, and a second position corresponding to a movement position, said controller providing instructions to said toy vehicle to move when said actuator is in said second position.
- 8. The toy of claim 7, said plurality of positions including a third position corresponding to a output generating position, said controller providing instructions to said toy vehicle to move and said housing generating an audible output when said actuator is in said third position.
- 9. A method of using a toy train set, the toy train set including a track, an output unit, a toy vehicle, and a remote control, the output unit including an output generating system, the method comprising:coupling the remote control to the output unit; and moving an actuator on the remote control from a first position to a second position to move the toy vehicle along the track; moving the actuator from the second position to a third position; and generating an audible output via the output unit, said generating an audible output occurring substantially simultaneously with said moving the actuator from the second position to a third position.
- 10. The method of claim 9, the remote control including a processor having a memory with a plurality of audible outputs stored therein, and said generating an audible output includes accessing at least one of said plurality of audible outputs.
- 11. The method of claim 9, said moving the actuator from the second position to a third position includes moving the actuator against a resilient member that biases the actuator from the third position to the second position.
- 12. The method of claim 9, the output unit including a speaker and a pair of contacts disposed on the output unit, the remote control including a processor having a memory with a plurality of audible outputs stored therein and a pair of contacts disposed on the remote control, said coupling the remote control to the output unit including disposing the remote control proximate to the output unit so that the contacts on the remote control engage the contacts on the output unit and the output generating system can access at least one of the audible outputs.
- 13. The method of claim 12, the remote control including a power supply, and said coupling the remote control to the output unit including providing power from the power supply to the output unit.
- 14. A method of controlling a plurality of toy vehicles using a control system, the control system including a first remote control, a second remote control, and a station, the method comprising:coupling the first remote control to the station; coupling the second remote control to the station; moving an actuator on the first remote control from a first position to a second position to move a first toy vehicle; moving an actuator on the second remote control from a first position to a second position to move a second toy vehicle; moving the actuator on the first remote control from its second position to a third position; and generating a first audible output via the station, said generating an audible output occurring substantially simultaneously with said moving the actuator on the first remote control from its second position to a third position.
- 15. The method of claim 14, further comprising:moving the actuator on the second remote control from its second position to a third position, said moving the actuator on the second remote control from its second position to a third position occurring independently of said moving the actuator on the first remote control from its second position to its third position; and generating a second audible output via the station, said generating a second audible output occurring substantially simultaneously with said moving the actuator on the second remote control from its second position to a third position.
- 16. A toy assembly comprising:a track; a first toy vehicle; a second toy vehicle; a first controller, said first controller being configured to control said first toy vehicle, said first controller including an audible output stored therein; a second controller, said second controller being configured to control said second toy vehicle; an output unit, said output unit being configured to receive said first controller and said second controller, said first controller being operable in a hand-held configuration and in a docked configuration in which said first controller is coupled to said output unit, said output unit being configured to generate said audible output when said first controller is in said docked configuration.
- 17. The toy assembly of claim 16, said second controller including an audible output stored therein, said second controller being operable in a hand-held configuration and in a docked configuration in which said second controller is coupled to said output unit, said output unit being configured to generate said audible output of said second controller when said second controller is in its docked configuration.
- 18. The toy assembly of claim 16, said first controller having a housing and an actuator that is movable relative to said housing, said actuator being disposable in a first position, a second position, and a third position.
- 19. The toy assembly of claim 18, said first position being an off position, said second position being an on position for said first vehicle, and said third position being an on position with an audible output.
- 20. The toy assembly of claim 19, said output unit generating an audible output associated with said first toy vehicle when said first controller is coupled to said output unit and said first controller actuator is moved to said third position.
US Referenced Citations (30)