Trolling motor bow mount impact protection system

CROSS REFERENCE RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §120 from co-pending U.S. patent application Ser. No. 09/592,023 entitled TROLLING MOTOR SYSTEM, filed on Jun. 12, 2000, now U.S. Pat. No. 6,325,685 which in turn claims priority under 35 U.S.C. §119(e) from U.S. Provisional Patent Application Seral No. 60/138,890 entitled TROLLING MOTOR, filed on Jun. 11, 1999 by Darrel A. Bernloehr et al.; and further claims priority under 35 U.S.C. §120 from U.S. Pat. No. 6,276,975 entitled TROLLING MOTOR BATTERY GAUGE, issued on Aug. 21, 2001 by Steven J. Knight; U.S. patent application Ser. No. 09/590,914 entitled TROLLING MOTOR STEERING CONTROL, filed on Jun. 9, 2000 by Steven J. Knigh, now U.S. Pat. No. 6,325,684; and U.S. patent application Ser. No. 09/591,862 entitled TROLLING MOTOR FOOT CONTROL WITH FINE SPEED ADJUSTMENT, filed on Jun. 12, 2000 by Steven J. Knight. The present application is related to U.S. Pat. No. 6,254,441 entitled TROLLING MOTOR PROPULSION UNIT SUPPORT SHAFT, issued on Jul. 3, 2001 by Steven J. Knight et al.; U.S. patent application Ser. No. 29/124,838 entitled TROLLING MOTOR FOOT PAD BASE, filed on Jun. 13, 2000 by Steven J. Knight et al.; U.S. patent application Ser. No. 29/124,860 entitled TROLLING MOTOR FOOT PAD PEDAL, fied, on Jun. 13, 2000 by Steven J. Knight et al.; U.S. patent application Ser. No. 09/593,075 entitled TROLLING MOTOR BOW MOUNT, filed on Jun. 13, 2000 by Steven J. Knight et al.; U.S. patent application Ser. No. 29/124,847 entitled TROLLING MOTOR PROPULSION UNIT SUPPORT SHAFT, filed on Jun. 13, 2000 by Steven J. Knight et al.; U.S. patent application Ser. No. 29/124,846 entitled TROLLING MOTOR MOUNT, filed on Jun. 13, 2000 by Ronald P. Hansen; and U.S. patent application Ser. No. 29/124,859 entitled TROLLING MOTOR MOUNT, filed on Jun. 13, 2000 by Ronald P. Hansen; the full disclosures of which, in their entirety, are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to outboard trolling motors. In particular, the present invention relates to a mounting mechanism for mounting an outboard trolling motor to a bow of a boat while protecting the trolling motor during unintended impact with underwater obstructions.

BACKGROUND OF THE INVENTION

Fishing boats and vessels are often equipped with an outboard trolling motor for providing a relatively small amount of thrust to slowly and quietly propel the boat or vessel while an operator is fishing. Although lightweight and easy to maneuver, such trolling motors have long been plagued by their vulnerability to impact with submerged objects such as tree stumps, roots, rocks and the like. These impacts can cause permanent damage to the trolling motor, its mounting structure, the boat itself, or to all three.

Bow mounted trolling motors are especially vulnerable to impacts with submerged objects because such bow mounted trolling motors are positioned in front of the boat. In an attempt to prevent or minimize damage caused by accidental collision with underwater objects, many bow mounted trolling motors are provided with break-away mounts that allow the entire motor assembly to swing or pivot upon impact with a submerged object. To absorb energy and to return the trolling motor to the original, generally vertical, orientation, the mounting mechanisms are additionally provided with springs or other shock-absorbing members.

Many trolling bow motor-mount systems allow the trolling motor lower propulsion unit to pivot both forwardly and rearwardly when encountering underwater obstructions. Although such multi-directional bow mount systems react to obstructions when the boat is moving both forwardly and rearwardly, such systems require springs or other shock absorbing members having a sufficient rigidity so as to withstand the forward thrust generated by the propulsion unit during normal operating conditions. As a result, such systems are generally capable of responding only to extremely large forces during such collisions.

As an alternative, other trolling motor bow mount systems allow uni-directional pivoting of the trolling motor. Examples of such mounting systems are disclosed in U.S. Pat. Nos. 4,033,530 and 3,915,417. In such systems, a telescopic upper arm including a spring is angularly mounted between the chassis affixed to the bow of the boat and the trolling motor pivotally mounted to the chassis. During a collision with an underwater object while the boat is moving in a forward direction, the trolling motor pivots about a first axis to extend the telescopic upper arm against the biasing force of the spring on the upper arm. The telescopic upper is generally only extensible in a single direction, preventing the forward thrust generated by the trolling motor from pivoting the propulsion unit in a reverse direction. To enable the lower propulsion unit to be withdrawn from the water, the trolling motor propulsion unit pivots about a second axis distinct from the first axis. Although such unidirectional bow mount systems enable more sensitive shock-absorbing members to be employed, such existing systems are extremely complex and occupy valuable space.

Thus, there is a continuing need for a trolling motor bow mount system that is simple and has fewer parts, that is lightweight and compact, that allows the trolling motor to be withdrawn from the water when not in use and that provides unidirectional obstruction-responsive pivotal movement of the trolling motor and its propulsion unit.

SUMMARY OF THE INVENTION

The present invention provides a bow mount trolling motor for a boat. The bow mount trolling motor includes a chassis adapted to be coupled to a bow of the boat, a housing pivotally coupled to the chassis about a first axis, at least one shaft extending along a second axis and movably coupled to the housing for movement along the second axis relative to the housing, a lower propulsion unit coupled to the at least one shaft, a stationary engagement surface coupled to the chassis and a resilient bias member coupled between the housing and the engagement surface.

The present invention also provides a bow mount trolling motor for use with a boat, wherein the motor includes a chassis adapted to be mounted to a bow of the boat, a lower propulsion unit and at least one shaft supporting the lower propulsion unit and pivotally coupled to the chassis about a first axis. The at least one shaft pivots in a first direction about the first axis from a deployed position to a stowed position and pivots in an opposite second direction about the first axis when the at least one shaft or the lower propulsion unit encounters an obstruction while the boat is moving in a forward direction.

The present invention also provides a bow mount trolling motor for use with a boat, wherein the motor includes a chassis adapted to be coupled to a bow of the boat, a lower propulsion unit, at least one shaft supporting the lower propulsion unit and pivotally coupled to the chassis about a first axis while extending along a second axis, a first engagement surface coupled to the chassis, a second engagement surface coupled to the at least one shaft and a resilient bias member coupled between the first engagement surface and the second engagement surface. The resilient bias member extends along an axis parallel to the second axis.

The present invention also provides a bow mount trolling motor for a boat which includes a chassis adapted to be coupled to a bow of the boat, a housing pivotally coupled to the chassis about a first axis and including a first engagement surface, at least one shaft extending along the second axis, a lower propulsion unit coupled to the at least one shaft, a coupling member moveably coupled to the housing and including a second engagement surface and a resilient bias member disposed between the first engagement surface and the second engagement surface. The coupling member is actuatable between a first position in which the coupling member is stationarily secured to the chassis against movement about the first axis and a second position in which the coupling member is movable about the first axis. The housing, the at least one shaft and a lower propulsion unit pivot in a first direction about the first axis relative to the coupling member when the coupling member is in the first position such that energy is absorbed by the resilient bias member. The coupling member, the housing, the at least one shaft and the lower propulsion unit all pivot in a second direction about the first axis to allow the lower propulsion unit to be pivoted to a stowed position when the coupling member is in the second position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a perspective view of an exemplary trolling motor system of the present invention employed on a boat with an underwater sonar system.

FIG. 2

is a side elevational view illustrating the trolling motor system of

FIG. 1

being dismounted from the boat by means of a bow mount system.

FIG. 3

is a sectional view of the bow mount system of

FIG. 2

taken along lines

3

—

3

.

FIG. 4

is a sectional view of the bow mount system of

FIG. 3

illustrating a chassis lowered onto a base of the bow mount system.

FIG. 5

is a bottom elevational view of the bow mount system of

FIG. 4

taken along lines

5

—

5

.

FIG. 6

is a sectional view of the bow mount system of

FIG. 5

taken along lines

6

—

6

.

FIG. 7

is a sectional view of the bow mount system of

FIG. 2

taken along lines

3

—

3

illustrating chassis and the base moved relative to one another in a sirs direction.

FIG. 8

is a bottom elevational view of the bow mount system of

FIG. 7

taken along lines

8

—

8

.

FIGS. 9A and 9B

are sectional views of a first alternative embodiment of the bow mount system of

FIG. 2

illustrating a chassis being secured to a base.

FIGS. 10A and 10B

are sectional views of a second alternative embodiment of the bow mount system of

FIG. 2

illustrating a chassis being secured to a base.

FIGS. 11 and 12

are exploded perspective views of a housing, drive system and impact protection system of the trolling motor system of FIG.

1

.

FIG. 13

is a fragmentary side elevational view of a shaft support of the trolling motor system of

FIG. 1

with portions removed for purposes of illustration.

FIG. 14

a sectional view of the shaft support of

FIG. 13

taken along lines

14

—

14

.

FIG. 15

is a sectional view of an alternative embodiment of the shaft support of FIG.

13

.

FIG.

16

. is a schematic illustration of a drive system of the trolling motor system of FIG.

1

.

FIG. 17

is a side elevational view of the trolling motor system of

FIG. 1

in a first deployed position.

FIG. 18

is a side elevational view of the trolling motor system of

FIG. 1

in a second raised deployed position.

FIG. 19

is a side elevational view of the trolling motor system of

FIG. 1

being pivoted and linearly moved towards a stowing position.

FIG. 20

is a side elevational view of the trolling motor system of

FIG. 1

being linearly moved to a fully stowed position.

FIG. 21

is a perspective view of the drive system of

FIG. 1

assembled and supported by a housing adjacent to a shaft support with selected portions removed for purposes of illustration.

FIG. 22

is a left side elevational view of a housing, a shaft support, a drive system and an impact protection system (collectively referred to as a stow and deploy unit) of the trolling motor system of

FIG. 1

with a side of the housing removed for purposes of illustration.

FIG. 23

is a right side elevational view of the unit of the trolling motor system of

FIG. 1

with a portion of the housing removed for purposes of illustration.

FIG. 24

is a rear elevational view of the unit shown in FIG.

21

.

FIG. 25

is a sectional view of the unit of

FIG. 22

taken along lines

25

—

25

.

FIG. 26

is a sectional view of the unit of

FIG. 22

taken along lines

26

—

26

.

FIG. 27

is a schematic sectional view of the shaft support of the trolling motor of

FIG. 1

illustrating a car along the shaft support.

FIG. 28

is a side elevational view of the unit of

FIG. 1

during Phase II.

FIG. 29

is a sectional view of the unit of

FIG. 28

taken along lines

29

—

29

.

FIG. 30

is a sectional view of the unit of

FIG. 28

taken along lines

30

—

30

.

FIG. 31

is a fragmentary side elevational view of the unit in Phase III.

FIG. 32

is a schematic view of a first alternative embodiment of the drive system FIG.

16

.

FIG. 33

is a schematic view of a second alternative embodiment of the drive system of FIG.

16

.

FIG. 34

is a schematic view of a third alternative embodiment of the drive system of FIG.

16

.

FIGS. 35 and 36

are schematic views of alternative linear drives for the drive system of the trolling motor system of FIG.

1

.

FIGS. 37 and 38

are schematic views of alternative pivot drives for the drive system of the trolling motor system of FIG.

1

.

FIG. 39

is a side elevational view of the trolling motor system of

FIG. 1

illustrating a propulsion unit encountering an underwater obstruction and pivoting rearwardly.

FIG. 40

is a side elevational view of the unit during the impact shown in

FIG. 39

with portions removed for purposes of illustration.

FIG. 41

is a side elevational view of the unit and adjacent chassis taken lines

41

—

41

of FIG.

25

.

FIGS. 42 and 43

illustrate the unit and adjacent chassis of

FIG. 41

as the trolling motor system is moved towards a stowed position.

FIG. 44

is a top elevational view of a foot control of the trolling motor system of FIG.

1

.

FIG. 45

is a schematic of the foot control of FIG.

44

.

FIG. 46

is a fragmentary perspective view of the foot control of

FIG. 44

with portions removed for purposes of illustration.

FIG. 47

is a fragmentary perspective exploded view of the foot control of

FIG. 44

with portions removed for purposes of illustration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Overview

FIG. 1

is a perspective view of an exemplary embodiment of the trolling motor system

50

employed on boat

52

with underwater sonar system

54

. Boat

52

is a conventionally known boat or vessel which generally extends along a longitudinal axis from a front or bow

56

to a rear or stern terminating at a transom (not shown). In the exemplary embodiment, bow

56

includes a generally flat mounting surface or deck

60

upon which trolling motor system

50

is supported. As will be appreciated, boat

52

may have a variety of alternative sizes, shapes and configurations.

Underwater sonar system

54

is conventionally known and provides data depicting or identifying underwater objects such as fish and terrain. Underwater sonar system

54

generally includes transducer

70

, transducer line

72

and control/display unit

74

. Transducer

70

is conventionally known and mounts to propulsion unit

400

of trolling motor system

50

in a well known manner. Transducer

70

transmits and receives signals to identify underwater objects and terrain. Transducer line

72

connects transducer

70

to control/display unit

74

and transmits signals from transducer

70

to display unit

74

. Display unit

74

provides visual and sound information regarding such detected underwater objects and terrain. Transducer line

72

preferably comprises one or more bundled wires. As shown by

FIG. 1

, transducer line

72

is at least partially housed and protected by trolling motor system

50

as described in greater detail hereafter.

Trolling motor system

50

generally includes bow mount system

100

, housing

200

, shaft support

300

, propulsion unit

400

, head

450

, drive system

500

(shown in FIG.

16

), impact protection system

800

(shown in

FIG. 40

) and foot control

900

. Bow mount system

100

generally includes base

102

and chassis

104

. Base

102

mounts to deck

60

and provides a support structure upon which chassis

104

may be releasably attached. In the exemplary embodiment, base

102

is screwed, bolted or otherwise permanently fastened to deck

60

. It is also contemplated that base

102

may be co-molded with or integrally formed as part of deck

60

in some applications.

Chassis

104

releasably mounts to base

102

and provides a stationary frame or bracket for supporting housing

200

, shaft support

300

, propulsion unit

400

, head

450

, drive system

500

and impact protection system

800

relative to boat

52

. In particular, chassis

104

pivotally supports housing

200

about axis

106

. As best shown by

FIG. 2

, bow mount system

100

enables trolling motor system

50

(shown in a fully stowed position) to be simply lifted and removed from deck

60

in the direction indicated by arrow

107

upon chassis

104

being released from base

102

.

Housing

200

is pivotally coupled to chassis

104

about axis

106

and movably supports shaft support

300

and propulsion unit

400

for movement along axis

202

of shaft support

300

. Housing

200

optionally includes motor rests

204

upon which propulsion unit is positioned when system

50

is in a fully stowed position. Housing

200

further provides a frame or base structure for supporting drive system

500

and impact protection system

800

. Although housing

200

preferably encloses and protects drive system

500

and impact protection system

800

, housing

200

may alternatively comprise an open frame or base which supports such assemblies and systems.

Shaft support

300

includes at least one shaft and is movably coupled to housing

200

for movement along axis

202

while supporting propulsion unit

400

at a lower end

302

and head

450

at an upper end

304

. In addition to supporting such structures, shaft support

300

facilitates steering of propulsion unit

400

and movement of propulsion unit

400

into and out of the water during stow, trim and deploy operations. Shaft support

300

further guides and protects transducer line

72

extending from transducer

70

to control/display unit

74

.

Propulsion unit

400

comprises a conventionally known lower motor prop which, upon being powered, drives a propeller

402

to generate thrust. Although propulsion unit

400

is illustrated as comprising a conventionally known motor prop with a propeller, propulsion unit

400

may alternatively comprise other devices for generating thrust under water such as jets and the like. Propulsion unit

400

is electrically coupled to head

450

and foot control

900

via wiring extending through shaft support

300

.

Head

450

is supported atop shaft support

300

and includes a known steering drive

452

(shown in

FIG. 13

) connected to propulsion unit

400

to rotatably drive propulsion unit

400

about axis

202

to direct the thrust generated by propulsion unit

400

in a desired direction. Steering drive

452

is electronically coupled to foot control

900

. Propulsion unit

400

may be steered in response to input from the operator's foot. Head

450

further includes manual inputs for controlling the amount and direction of thrust generated by propulsion unit

400

. In lieu of including steering drive

452

, head

450

may alternatively or additionally include a conventionally known control arm or tiller allowing manual steering of propulsion unit

400

.

In addition to providing manual, hand operator interfaces to control various aspects of propulsion unit

400

, head

450

also provides various information regarding propulsion unit

400

and its source of power, preferably a battery

454

. In the exemplary embodiment, head

450

includes a display that indicates the amount of charge remaining within the battery

454

and the amount of time remaining until the battery is either exhausted or past a pre-selected point of charge based upon the current RPM or amount of thrust being generated by propulsion unit

400

. Head

450

may also display an estimated amount of distance that can be traveled at the existing RPM or thrust output of propulsion unit

400

. Moreover, head

450

may be operably or electronically tied in with global positioning system (GPS) or other location identifying mechanisms, wherein head

450

generates an alarm or other notification signal to notify the user when progress towards a recorded home position must be begun based upon the calculated or input distance from the home position, based on the current battery charge and based on the current RPM or thrust output of propulsion unit

400

. A more detailed description of such operations is described in U.S. Pat. No. 6,276,975, by Steven J. Knight, entitled TROLLING MOTOR BATTERY GAUGE and issued on Aug. 21, 2000, the full disclosure of which, in its entirety, is hereby incorporated by reference. Similar controls for propulsion unit

400

are provided by foot control

900

.

Drive system

500

(shown in

FIG. 16

) moves shaft support

300

and propulsion unit

400

during trim, stow and deploy operations. In particular, linear drive

504

linearly moves shaft support

300

and propulsion unit

400

along axis

202

. Pivot drive

506

pivots housing

200

about axis

106

to reposition shaft support

300

and propulsion unit

400

from a generally vertical orientation to a generally horizontal orientation. In the exemplary embodiment, both linear drive

504

and pivot drive

506

share an actuator

502

(shown in

FIG. 25

) which provides power, in the form of torque, to both drives. Alternatively, linear drive

504

and pivot drive

506

may be provided with dedicated actuators. Actuator

502

preferably comprises an electrically powered motor. Although less desirable, other actuators may be used in lieu of actuator

502

.

Impact protection system

800

(shown in

FIG. 40

) is coupled between chassis

104

and housing

200

. Impact protection system

800

enables shaft support

300

and propulsion unit

400

to pivot in a generally rearward direction towards stern

58

of boat

52

as indicated by arrow

802

when encountering an underwater obstruction when boat

52

is moving in a forward direction. During such impacts, impact protection system

800

further absorbs energy to slow the forward progression of boat

52

and to reduce damage to shaft support

300

and propulsion unit

400

. In addition to protecting propulsion unit

400

, shaft support

300

, bow mount system

100

and boat

52

itself from damage as a result of collisions with underwater obstructions, impact protection system

800

also permits housing

200

, shaft support

300

and propulsion unit

400

to pivot in a generally forward direction towards bow

56

of boat

52

as indicated by arrow

804

. As a result, housing

200

, shaft support

300

and propulsion unit

400

may be pivoted from a generally vertical deployed orientation to a generally horizontal stowed position. Pivotal movement of housing

200

, shaft support

300

and propulsion unit

400

in the opposite directions indicated by arrows

802

and

804

occurs about a single pivot point, axis

106

. As a result, impact protection system

800

is simpler and less complex as compared to prior conventional systems for protecting bow mounted trolling motors during collisions with underwater obstructions.

Foot control

900

is electronically coupled to drive system

500

and is coupled to propulsion unit

400

via head

450

. Foot control

900

generally comprises a foot pad

904

supporting and housing a plurality of operator interfaces

906

by which the operator can control various aspects of drive system

500

and propulsion unit

400

with his or her foot or feet. In the exemplary embodiment, interfaces

906

are electronically coupled to a control circuit supported in either pad

904

, head

450

or propulsion unit

400

which generates control signals to control aspects of drive system

500

and propulsion unit

400

. In the exemplary embodiment, interfaces

906

control the speed of propeller

402

of propulsion unit

400

and the resulting thrust generated by propulsion unit

400

, the direction of thrust generated by propulsion unit

400

, the vertical height or trim of shaft support

300

and propulsion unit

400

along axis

202

and deployment or stowing of shaft support

300

and propulsion unit

400

. Such operational control provided by foot control

900

is set forth and described in greater detail in co-pending U.S. patent application Ser. No. 09/590,914, entitled TROLLING MOTOR STEERING CONTROL by Steven J. Knight and filed on Jun. 9, 2000, now U.S. Pat. No. 6,325,684, the full disclosure of which, in its entirety, is hereby incorporated by reference.

Bow Mount System

FIGS. 3-8

illustrate base

102

and chassis

104

of bow mount system

100

in greater detail. As best shown by

FIG. 3

, base

102

is secured to deck

60

by fasteners

108

and generally includes dovetails

110

,

112

. Dovetails

110

,

112

project from base

102

to form side projections

118

and side channels

120

which face and extend sideways in a common direction. Chassis

104

includes dovetails

114

,

116

. Dovetails

114

,

116

extend from chassis

104

and form side projections

122

and side channels

124

to face and extend in a common direction opposite to projections

118

and channels

120

. Channels

124

are configured to receive projections

118

while channels

120

are configured to receive projections

122

. In the exemplary embodiment, dovetails

114

,

116

are configured to complement dovetails

110

,

112

such that dovetails

110

,

112

may be mated with dovetails

114

,

116

. In the exemplary embodiment, dovetails

110

,

112

and dovetails

114

,

116

extend along substantially the entire axial length of base

102

and chassis

104

, respectively, for optimum mounting strength and rigidity. Alternatively, dovetails

110

,

112

and dovetails

114

,

116

may extend along only a portion of the axial length of base

102

and chassis

104

or may be intermittently spaced along the axial length of base

102

and chassis

104

. As shown by

FIG. 4

, dovetails

110

,

112

and dovetails

114

,

116

are transversely spaced from one another so as to enable chassis

104

to be lowered onto base

102

with dovetails

110

,

112

,

114

and

116

in an interleaved relationship with dovetail

114

positioned between dovetails

110

and

112

and with dovetails

110

,

112

and dovetails

114

,

116

in a non-mating or non-engaged relationship.

As further shown by

FIGS. 3

,

5

and

6

, bow mount system

100

additionally includes an actuation and retaining mechanism

128

between base

102

and chassis

104

. Actuation mechanism

128

generally includes puck

130

and drawbar assembly

132

. Puck

130

generally comprises a projection or protuberance generally extending from chassis

104

. In the exemplary embodiment, puck

130

is fastened to chassis

104

. Alternatively, puck

130

may be integrally formed with chassis

104

. Puck

130

provides first actuation surface

134

which cooperates with drawbar assembly

132

to cause sideways movement of chassis

104

relative to base

102

to bring about inter-engagement of dovetails

110

,

112

,

114

and

116

.

Drawbar assembly

132

is provided as part of base

102

and generally includes tracks

138

, drawbar

140

, spring

142

and lever

144

. Tracks

138

extend from base

102

on opposite sides of drawbar

140

. Tracks

138

slidably engage drawbar

140

to slidably secure drawbar

140

to base

102

such that drawbar

140

may be axially moved along axis

146

. Alternatively, other mechanisms may be used to movably support drawbar

140

for movement along axis

146

.

Drawbar

140

comprises an elongate rigid member slidably disposed between tracks

138

and including window

148

. Window

148

extends at least partially through drawbar

140

and is sized to receive puck

130

when chassis

104

is lowered onto base

102

. Window

148

is preferably continuously bounded and provides a second actuation surface

150

configured to interact with first actuation surface

134

of puck

130

when drawbar

140

is moved along axis

146

. During such interaction, chassis

104

and its dovetails

114

,

116

are moved in a sideways direction to engage dovetails

110

and

112

, respectively. Because window

148

is continuously bounded, reception of puck

130

by window

148

further retains chassis

104

axially with respect to base

102

.

As shown in

FIGS. 5 and 8

, drawbar

140

and actuation surface

150

move along axis

146

between a locking position (shown in

FIG. 8

) and a releasing position (shown in FIG.

5

). In the releasing position, actuation surface

150

is disengaged from actuation surface

134

such that puck

130

may be moved sideways within window

148

and such that dovetails

114

,

116

may be moved sideways and disengaged from dovetails

110

,

112

, respectively, to permit chassis

104

to be lifted and separated from base

102

. In the locking position, actuation surface

150

has engaged actuation surface

134

to move chassis

104

relative to base

102

, to wedge puck

130

in window

148

, and to engage dovetails

114

,

116

with dovetails

110

,

112

, respectively. As a result, chassis

104

is secured to base

102

in a vertical direction and in a sideways direction.

Spring

142

is coupled between drawbar

140

and base

102

and resiliently biases drawbar

140

to the releasing position. As will be appreciated, various other resilient biasing mechanisms may be used in lieu of spring

142

.

Lever

144

is coupled between base

102

and drawbar

140

and actuates drawbar

140

along axis

146

against the bias of spring

142

. In the exemplary embodiment, lever

144

is pivotally coupled to drawbar

140

about axis

154

. Axis

154

, about which lever

144

is pivotally coupled to drawbar

140

, is spaced from side of base

102

by differing extents (X and X′) depending upon the orientation of lever

144

about axis

154

such that rotation of lever

144

about axis

154

draws or moves drawbar

140

along axis

146

.

FIGS. 3-8

further illustrate the method by which chassis

104

is releasably secured to base

102

. As shown in

FIGS. 3 and 4

, chassis

104

is first lowered onto base

102

such that projection

122

of dovetail

114

extends between side channels

120

of dovetails

110

and

112

. As shown in

FIG. 8

, lever

144

is then rotated in the direction indicated by arrow

160

to move drawbar

140

along axis

146

in the direction indicated by arrow

162

. As a result, actuation surfaces

134

and

150

engage one another to move chassis

104

and side projections

122

of dovetails

114

,

116

in a sideways direction as indicated by arrow

164

in

FIG. 8

relative to base