BACKGROUND OF THE INVENTION

Aerial work platforms have been developed and in use for more than twenty five years. Their primary purpose is to raise workers quickly and safely to positions to do necessary work. They replace earlier means of access such as ladders and scaffolds. Some models can also reach below a surface or a long horizontal distance from the surface on which they are located, and some types of lifts can place workers as high as 150 to 250 feet above the ground.

The first three of the following make up the major population of such machines:

1. Vehicle-Mounted Elevating and Rotating Aerial Devices as covered by ANSI/SIA A92.2-1990. These machines are typically mounted on a commercial truck chassis but may be mounted on a trailer chassis and are used in erection and maintenance of utility lines. They include models where the work platform is supported by an articulating or a telescoping boom which is mounted on a turntable that can rotate about a vertical axis.

2. Boom-Supported Elevating Work Platforms as defined in ANSI/SIA A92.5-1992. These machines are self-propelled, typically have a telescoping and/or articulating boom and are used in construction and maintenance tasks.

3. Self-Propelled Elevating Work Platforms as defined in ANSI/SIA A92.6-1990. These machines (typically scissor-lifts) elevate the work platform vertically but do not position the platform horizontally completely outside the base on which it is supported. They are also used in general construction and maintenance tasks.

4. Manually Propelled Elevating Work Platforms as defined in ANSI/SIA A92.3-1990. These machines are manually propelled and have platforms that cannot be positioned completely outside the base.

5. Airline Ground Support Vehicle-Mounted Vertical Lift Devices as defined in ANSI/SIA A92.7-1990. These are machines designed specifically for aircraft servicing and maintenance.

6. Vehicle-Mounted Bridge Inspection and Maintenance Devices as defined in ANSI/SIA A92.8-1993. These machines are designed to reach out, down and under a bridge for inspection and maintenance.

7. Mast-Climbing Work Platforms as defined in ANSI/SIA A92.9. These machines are designed to place several workers on a platform along a wall or similar vertical surface to do extensive operations.

Controls for operating most of the types of aerial platforms mentioned above are comprised of electrical switches or other devices mounted at an operator's station on the platform. These electrical devices control valves or other means on the chassis which in turn activate hydraulic or electrically powered devices such as cylinders or motors. Mechanical controls are difficult or impossible to use for controls on the platform because of the distance from the platform to the chassis and the mechanical positioning of the platform relative to the chassis in order to reach the desired work location. Likewise, it is difficult and inefficient, except in the simplest machines, to route multiple hydraulic lines with hoses at mechanical joints up to the platform where hydraulic valves could be used to control machine motions. Therefore, the industry practice has evolved to the use of electrical switches and controllers on the platform which actuate hydraulic or electrical means on the chassis to cause the desired motion. Two general types of electrical devices are (1) the simple on/off switch that may be actuated in two directions, e.g., up or down, and usually is spring loaded to return to neutral, and (2) the controller type of switch that usually provides an electrical output signal proportional to the displacement of the handle of the controller. The proportional controller is important to the operator and is used to make smooth starts and stops and to move at a reduced rate of speed as existing conditions may make desirable. Proportional controllers are used on most sophisticated aerial work platforms and on those providing greater platform height. The two types are used interchangeably in this document and it will be understood that the word “switch” is to be interpreted broadly and includes a controller, and vice versa.

Switches were typically located on the operator's control panel in patterns which may have been influenced by aesthetics, space considerations and fabrication economy. Beginning in 1980, the applicable consensus standard for boom-supported elevating platforms (ANSI A92.5-1980) specified that “all directional controls shall move in the direction of the function which they control when possible, and shall be of the type which return to the ‘off’ or the neutral position when released. Such controls shall be protected against inadvertent operation.” Directional controls are defined in the ANSI A92.5-1980 Standard as “all controls necessary to raise, lower, rotate, telescope, drive or otherwise initiate the powered functions of the work platform.” A similar requirement had first appeared in the ANSI A92.6-1979 Standard on Self-propelled Elevating Work Platforms, albeit without the definition of “directional controls.”

One design with clear advantages with respect to earlier control arrangements is disclosed and described in U.S. Pat. No. 4,331,215—Grove et al. This patent discloses controls that are individual electric devices mounted on a surface slightly inclined to the vertical or on a second surface slightly inclined to the horizontal. This arrangement permits all of the controls to operate in substantially the same direction in which the platform moves as a result of the control activation. This design meets the requirement of the applicable consensus standard (ANSI A92.5-1980) and provides an approach that minimizes operator error, a major cause of accidents on aerial work platforms.

As noted in the Grove et al. patent workers such as electricians, painters, sandblasting operators, bricklayers and carpenters using these machines are skilled primarily in the area of their work specialty and the aerial platform they are using serves solely as a positioning means, hence, many operators do not become proficient as do the trained operators of cranes or earth-moving machinery who do nothing but operate such machines full time. Moreover, operators of aerial platforms may use one machine for a few days and may then be assigned a different make and model that has a different control arrangement, or may even rent different machines for use on an “as needed” basis. Although operators of aerial platforms are required to be trained, such training may be limited and often does not include specific training on the control variations used on different makes and models. Therefore, the opportunity for inadvertent errors is increased by the requirement for the operator to first select the proper control, second, to check to be certain of which way to operate the control handle, and third, to then implement the control operation.

Other machines utilize controls which differ from the typical steering wheel, accelerator, brake, and gear shift with which most people are familiar. Various construction vehicles such as skid-steer loaders, bulldozers, and front end loaders are provided with control levers usually based on the mechanical devices which effect the motion but do not necessarily move in a direction of the motion caused nor do they provide a simulated model of the machine for quick operator recognition and orientation. Certain models of power lawn mowers currently available also utilize levers to effect driving and steering but lack the analogous motion and the simulated model of the machine for quick operator recognition and orientation. Another control layout which was developed on early aircraft and is still used on certain light aircraft and military fighters is the pilot's cockpit control stick. When the control stick is pushed to the left, the aircraft rolls to the left in response; when the stick is pushed forward, the aircraft rotates nose downward in response. However, the control stick does not provide the third axis control for the rudder, and, most importantly, does not provide the simulated model which ensures the quick recognition and orientation needed for aerial platform operators. Pilots are required to be trained and licensed, even for light civilian aircraft, while military aircraft can only be flown by pilots who have hundreds of hours of training and flight experience. On the other hand, training of aerial platform operators is often minimal; indeed, a worker at a large construction site will often come upon an aerial platform not in use, will start it if possible, and will proceed to use it without permission or any training.

Further requirements for the operator's controls are specified in the ANSI/SIA A92.6-1990 Standard for Self-Propelled Elevating Work Platforms that require that the upper controls (on the platform) shall “include a control which shall be continuously activated in order for upper directional controls to be operational and which automatically returns to the off position when released.” A similar requirement is specified in the ANSI/SIA A92.5-1992 Standard for Boom-Supported Elevating Work Platforms by specifying that the upper controls provided at the platform shall “include a separate safety control which shall be continuously activated for upper directional controls to be operational, and which renders upper directional controls inoperative when released.” These requirements have typically been met by having a separate foot pedal or an equivalent switch that must be operated by the operator in order for the directional controls to be used. A foot pedal can be actuated by the operator while using one hand to operate the directional control. However, in addition to the cost and installation expense, the foot pedal requires an electrical cord connection which must be durable, and together with the pedal is subject to rough service, deterioration due to weather conditions and damage from falling objects. A separate hand switch may be utilized but the operator may then be required to use both hands. A safety control may be integrated into each directional control but this would require three or more duplicate safety switches, with the controls of each capable of being released by the operator if he or his hand is trapped such that he cannot return the directional control to neutral. The safety control, in order to be most effective and provide maximum safety enhancement, must meet at least the following requirements:

1. It must prevent inadvertent operation of a directional control in case the directional control is struck by the operator, by other personnel or by a falling object or tool being used in performance of the work task;

2. When released it would preferably provide a signal to stop all powered functions if a malfunction occurs in the directional control or any other component of the control system;

3. When released it would preferably provide a signal to stop all powered functions if a malfunction occurs in any component of the power supply system; and

4. It would preferably provide a signal to stop or prevent unsafe powered motion that may be caused by a single point failure mode.

Thus, despite the advances made in the art, the control systems and arrangements discussed above are deficient in not providing a total human factors solution and in not utilizing a control configuration and mechanism that can provide rapid and certain recognition and orientation to both trained and untrained operators, resulting in increased safety and operator efficiency.

SUMMARY OF THE INVENTION

The present invention provides an analog control comprising a mechanism that operates with motions similar to those of the aerial platform and causes an equivalent motion of the aerial platform when operated. The shape of the overall control is similar, i.e., analogous to that of the aerial platform so that recognition and comprehension by the untrained operator is expedited and assured. A typical aerial platform comprises a platform and an elevating means preferably supported on a self-propelled chassis or on a commercial truck chassis. The rotating models utilize a turntable or turret which supports the elevating mechanism and may be rotated up to 360 degrees on a vertical axis. For such a machine having a telescoping boom, the analog control of the present invention incorporates several motion controls. First, swinging or rotating the turntable left or right about the vertical axis is controlled. Second, the raising or lowering the boom as supported on the turntable is controlled. Next, the extension or retraction of the telescoping boom is controlled.

In addition, by the use of an enable button-type switch (or other type switch) on the handgrip, additional functions may be controlled by the analog control of the present invention. For example, such a switch preferably controls driving forward and backward by pushing or pulling as in telescoping; steering left or right as in swing; raising or lowering jib boom or other boom apparatus; rotating the platform on a vertical axis at a point of attachment to the end of the boom; and tilting or leveling the platform on a horizontal axis to correct or adjust for minor deviations in the leveling system.

In preferred embodiments, the analog control of the present invention comprises a generally circular fixed structure attached to a control console or other structure convenient to the operator's station in a platform and a rotating mechanism supported by and attached to a fixed structure. The fixed structure assembly also provides actuating means for the switch which is mounted on the rotatable structure and causes rotation of the turntable of the aerial platform. The fixed structure includes a lockplate into which a pin is inserted to prevent motion of the control in swing (rotate) or lift (raise or lower the boom) directions. The structure of the rotating mechanism is preferably circular, rectangular or some combination thereof in the plan view and supports the lockplate matching that on the fixed structure. The switch or controller that causes motion of the boom in the lift or lower direction is attached to the inside of the rotating structural element and is actuated by raising or lowering the simulated boom which is attached on top of the rotatable structure by a bracket at one edge. The outer section of the simulated boom is attached by a pin or bolt to the bracket. The simulated boom also preferably includes an inner boom section which telescopes within the outer section. In certain embodiments a switch is mounted on the outer boom near the hinged end and is operated by telescoping motion of the inner boom to provide the equivalent motion by the telescoping boom of the aerial platform. In these embodiments a bracket is attached to the outer boom that, through a connecting link, controls the lift switch supported on the rotating structure, and thereby causes lifting or lowering of the boom of the aerial platform.

The inner tube of the simulated boom is attached to a handgrip at the outer end with a safety lever located so that it is convenient for the operator to squeeze the handgrip and safety lever with one hand. Also a part of the outer boom tube are brackets which support a pivot for the lock lever that acts as the detent or lock for swing and lift motions of the simulated boom control. The lock lever, in turn, is operated by the lock link when the operator pulls the safety lever toward the handgrip. Also mounted within the handgrip is an on/off safety switch that is activated by the final motion of the safety lever when squeezed. The safety switch, as specified in the consensus standards, must be actuated, i.e., in the “on” position, for the upper directional controls to be operational. Such a system renders the upper directional controls inoperative when released. The safety lever also supports and operates a detent thereby locking the inner tube of the simulated boom to the outer tube, and preventing telescoping motion unless the safety lever is operated.

Accordingly, it is an overall object of the present invention to provide an integrated and human-engineered directional control for use by the operator of an aerial platform. It is another object of the present invention to provide a control having a shape substantially analogous to the shape of the aerial platform it controls. It is a further object of this invention to provide a control having allowable motions substantially analogous to the motions of the aerial platform it controls.

It is yet another objective of the present invention to provide a control for aerial platforms that combines three or more directional controls into a single control assembly. It is another object of this invention to provide a control for aerial platforms which enhances safety by reducing the probability of the operator selecting the wrong control. It is a further object of the present invention to provide a control for aerial platforms which increases the work efficiency of the operator and of the aerial platform by reducing the time spent in selecting and operating separate controls for each motion desired. It is a still further object of this invention to expedite operator recognition and orientation of the control and its functions. Another object of this invention is to facilitate operator training by providing a control having a shape and motions substantially analogous to the aerial platform being controlled. It is another object of this invention to provide a control having mechanical detents or locks to prevent motion of the control unless the safety lever is operated. It is another object of this invention to prevent inadvertent operation of the control unless a safety lever is operated. Another object of this invention is to prevent accidental operation of the control by a falling tool or piece of material or by inadvertent contact by personnel. It is yet another object of this invention to incorporate a safety switch into the control which must be continuously actuated by the operator in order for the directional controls to be operational and which stops all powered functions when released.

It is an object of this invention to provide a control for aerial platforms with a safety switch which stops all powered motion of the aerial platform when the control is released by the operator in case of a malfunction of any component of the control system or the power supply system. It is another object of this invention to provide a control which can be operated by using one hand only. It is another object of this invention to avoid the need for a separate foot-operated or hand-operated safety switch. It is a still further object of this invention to provide a safety control which avoids the fabrication, assembly, installation and maintenance costs of a separate foot-operated or hand-operated safety switch.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a side elevation view, partially broken away, illustrating the analog control of the present invention;

FIG. 2

is a side elevation view, partially broken away, illustrating an alternate embodiment of the analog control of the present invention;

FIG. 3

is a side elevation view, partially broken away, showing another embodiment of the analog control of the present invention; and

FIG. 4

is a side elevation view, partially broken away, showing another embodiment of the analog control of the present invention.

FIG. 4A

shows a view taken through a portion of FIG.

4

.

FIG. 4B

shows a view taken through a portion of FIG.

4

.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments shown in the figures are explained with their advantages and applications. Those of skill in the art will understand that modifications and variations too numerous to present may be realized based upon the features and principles discussed herein, even though such modifications and variations will perform the same functions. It will therefore be understood that different mechanical components and geometry, as well as other electrical components, can be utilized on certain specific models of aerial platforms yet still use the present invention.

Referring now to

FIG. 1

, there is shown a control system for an aerial platform having a rotating turntable or turret on which a telescoping boom is supported. The turntable may be mounted on a self-propelled chassis (ANSI Type 2) or on a commercial truck chassis (ANSI Type 1). The boom may have two, three or more telescoping sections which fit within each other and are typically operated hydraulically for extension and retraction. The control simulates the upper works of the aerial platform, i.e., everything above the chassis of the supporting vehicle. In

FIG. 1

the fixed structure

11

is attached by suitable bolts or other means to the structure of the work platform at the operator's station in the platform. The rotating structure

12

is supported and attached by spindle

13

and by bolt

14

such that it can rotate left or right from the neutral position. That rotation will cause the bracket

15

to operate switch

16

mounted on rotating structure

12

by contact with roller

17

on the actuating lever of the switch, or conversely, if the rotating structure is rotated the opposite direction, the switch

16

will be operated in the other direction by a bracket equivalent to bracket

15

but on the near side of roller

17

. Switch

16

causes the turntable of the aerial platform to rotate in response to and in the same direction as the operator's control input. The rotation of the rotating structure

12

on the spindle

13

is facilitated by bearing

18

between the two parts. Also mounted on the rotating structure

12

is lift switch

19

which causes the boom of the aerial platform to be lifted or lowered with respect to the turntable. It can be noted that lift switch

19

, operated by link

20

which in turn is operated by bracket

21

and outer boom tube

22

to which bracket

21

is attached, will be operated in one direction if the outer boom tube

22

is raised and in the opposite direction if outer boom tube

22

is lowered. By appropriate circuitry the boom of the aerial platform will be caused to be raised or lowered analogous to the motion of the operator's input motion with the simulated boom of the control. The outer boom tube

22

is attached to the rotating structure

12

by a pin

23

through bracket

24

which is attached to rotating structure

12

. Also attached to outer boom tube

22

is bracket

25

on which telescope switch

26

is mounted. Switch

26

is operated by link

27

which is attached to and operated by the inside end of inner tube

28

. By sliding inner tube

28

in or out it can be seen that opposite motions will be imparted to telescope switch

26

which operate the telescope system of the aerial platform in an analogous motion. Inner tube

28

is attached to and moved by handgrip

29

which is to be operated by the operator.

The safety lever

30

is attached to and operated in conjunction with handgrip

29

. Incorporated in one leg of safety lever

30

is lock pin

31

which is engaged in matching holes in outer boom tube

22

and in inner boom tube

28

thereby locking the tubes together to prevent sliding of inner boom tube

28

within outer boom tube

22

unless lock pin

31

is withdrawn by operating safety lever

30

. Enclosed within a portion of handgrip

29

is safety switch

32

which is actuated by contact of safety lever

30

with the operating plunger of safety switch

32

. Safety switch

32

is typically a normally open switch which, when closed by operating lever

30

, causes the appropriate electrical circuitry to provide electrical power to the directional controls, in this embodiment the lift, telescope and swing switches mounted in the analog control. A thumb-actuated enable switch

34

may also be provided on the upper part of the handgrip

29

on the side opposite the connection to inner tube

28

. If appropriate for the specific model aerial platform, two or more of the enable switches may be provided to permit control of auxiliary functions.

If the control in

FIG. 1

is to be used on an aerial platform mounted on a self-propelled chassis (Type 2) driving and steering functions may also be accomplished using the analog control. In that embodiment enable switch

34

may be a push button type switch which is “on” only as long as it is depressed, or it may be a two-position toggle switch or a rocker switch with on/off positions to enable or disconnect the driving mode. When switch

34

is “on” it provides means such as relays and other circuitry to disconnect the telescope function from switch

26

and substitute the drive function. Likewise, operating switch

34

will cause the steering function to replace the swing function operating through switch

16

. Thus, in the driving mode, the operator will push the handgrip

29

forward operating switch

26

to drive forward and pull handgrip

29

rearward for reverse travel. Steering is accomplished by pointing the hinged end of the simulated boom in the desired direction, e.g., pointing to the left causes the aerial platform to steer left when driving forward. These motions of the aerial platform are also analogous to those of the analog control which caused the motions.

Safety lever

30

also provides a third function in addition to unlocking the telescope mechanism and operating the safety switch. When safety lever

30

is pulled by the operator it operates detent lever

38

through link

37

which is connected by a slot

40

in detent lever

38

. It can be seen in

FIG. 1

that operating safety lever

30

will cause detent lever

38

to withdraw lockpin

41

from fixed structure

11

and rotating structure

12

, thereby permitting up and down motion of the handgrip

29

and the simulated boom, and rotational motion of the handgrip

29

and rotating structure

12

. Thus, operating the safety lever

30

releases the handgrip

29

and the simulated boom to move in all three planes, 1) up and down to cause lifting and lowering of the aerial platform's boom, 2) telescoping in and out to cause retraction and extension of the aerial platform's telescoping boom, and 3) rotating left and right to cause swing left and right of the aerial platform's turntable.

Detent lever

38

is pivotally supported on a pin through bracket

39

which is attached to the outer tube

22

of the simulated boom. Hence, the detent lever must be provided with extra travel to have sufficient clearance from rotating structure

12

considering the telescoping of the simulated boom and the lowering of the simulated boom. Lockpin

41

is installed in a vertical slot in detent lever

38

so that it may be adjusted to accommodate production tolerances and the neutral position of switch

19

. A slot

40

is also located at the attachment of link

37

to detent lever

38

in order to permit the safety lever

30

to move sufficiently to release plunger

33

of safety switch

32

, thereby stopping all powered functions without moving detent lever

38

to its fully locked position, in case detent lever

32

is prevented from moving to its locked position due to displacement of one of the three motions away from neutral.

A small scale platform

35

is shown attached to the top of handgrip

29

. Different shapes and sizes of this platform may be used to provide a close simulation for a specific model aerial platform and to complete the shape of the analog control in its function in recognition by the operator and orientation of the operator. The platform

35

also supports instruction plate

36

which is located at that position to provide specific instructions for use of the analog control. Platform

35

also provides a third function as a horizontal guard over the operator's hand as protection from falling objects which might injure his hand or jam the analog control. While such guards are not normally installed on current controls, the analog control disclosed will provide this extra safety feature in order to ensure that the operator can release the safety lever

30

from contact with safety switch

32

.

It will be understood that springs are located such that the mechanism and switches for the directional controls will be returned to the neutral position shown in

FIG. 1

although not shown for clarity. Detent lever

38

and safety lever

30

are also spring loaded to return to the position shown in

FIG. 1

which locks the control against any motion regardless of the position when released by the operator. Likewise, the electrical connections and wiring to the switches are not depicted but may be routed within the simulated boom tubes and the rotating portion of the assembly culminating in a single bundle and connector which may pass through the fixed structure

11

or may interface with the wiring harness of the aerial platform at that approximate location.

The embodiment shown in

FIG. 2

is an analog control system for an aerial platform which elevates the work platform vertically but does not position the platform completely outside the base on which it is supported (Type 3). These machines are typically self-propelled scissorlifts but may be mounted on a truck chassis. As such, the primary control function to position the platform is to elevate or lower the platform. Hence, the embodiment in

FIG. 2

includes means to control driving and steering the chassis of a self-propelled aerial platform. If the machine under consideration is mounted on a truck chassis (Type 1) the drive and steer functions can be eliminated and the control can be greatly simplified.

The analog control in

FIG. 2

is supported on and attached to fixed support

51

which, in turn, is rigidly attached to support structure at the operator's station on the platform such that the right end of the control is toward the front of the aerial platform. The rotating assembly

52

is attached to fixed support

51

via bolt

54

and a suitable bearing

53

. Attached to the lower side of rotating assembly

52

is control switch

57

which provides signals to the steering mechanism. As rotating assembly

52

is pivoted the control switch

57

will be operated by contact of roller

55

on the operating lever of the switch with bracket

56

on fixed support

51

. If rotating assembly

52

is rotated the other direction roller

55

will contact an equivalent bracket thereby operating switch

57

in the opposite direction.

The elevating function is simulated in this embodiment by an elevating assembly

62

which is attached to rotating assembly

52

by two sets of parallel links designated

58

,

59

and

60

,

61

. In

FIG. 2

the right ends of these links are pivotally attached to two parallel vertical ribs

63

which are part of rotating structure

52

. The left ends of parallel links

58

,

59

and

60

,

61

are attached to two similar ribs

64

which are part of elevating assembly

62

. It can be seen that as elevating assembly

62

is raised, the parallel links will maintain the attitude of elevating assembly

62

with respect to fixed support

51

.

Part of elevating assembly

62

is beam

65

which may be a tube or a hat section in cross section. Beam

65

is rigidly attached to and becomes a part of elevating assembly

62

. Inner tube

66

is slidably engaged within beam

65

such that handle

67

can be used to slide tube

66

to the right or left as shown in FIG.

2

. This sliding motion is used to actuate drive switch

68

via link

69

which is attached to tube

66

near its right end. Thus, pushing handle

67

to the right will cause drive switch

68

to impart a drive/forward signal to the drive system and pulling handle

67

to the left will cause drive switch

68

to impart a drive/reverse signal to the drive system of the aerial platform.

Handle

67

is inserted into and attached to the left end

71

of tube

66

. Also attached to handle

67

is safety lever

70

which has a lock pin

72

that engages both tube

66

and beam

65

to cause locking of the drive motion. Safety switch

77

is mounted within handle

67

such that its operating plunger

78

will be actuated by safety lever

70

during its final motion as the operator squeezes safety lever

70

toward handle

67

. This operation of safety switch

77

at the end of the stroke of safety lever

70

is important so that the operator can release safety lever

70

and it will immediately release safety switch

77

to stop all motion of the aerial platform.

Also supported on and attached to handle

67

is a simulated platform

79

which may be shaped to resemble the aerial platform on which the analog control is to be used. The simulated platform is attached to handle

67

through spacer

80

in order to provide clearance from beam

65

. The right end of simulated platform

79

is attached to tube

66

via spacer

81

. A thumb actuated enable switch

82

may be provided on handle

67

to control auxiliary functions such as extending a platform extension. Two or more enable switches may be provided as appropriate for a specific model aerial platform. Shown on simulated platform

79

is support

73

for an instruction plate that may be provided at that location to give specific instructions for operating the analog control.

When safety lever

70

is pulled by the operator of the aerial platform it also operates bellcrank

84

via link

83

which connects to the safety lever

70

at a slot

74

. Slot

74

permits safety lever

70

to be released sufficiently to disengage safety switch

77

even though safety lever

70

cannot immediately return to the locked position shown in FIG.

2

. Bellcrank

84

is rotated counterclockwise when it is operated by link

83

thereby causing link

87

to pull back lock lever

86

from the locked position shown in FIG.

2

. In that position lock pin

88

of lock lever

86

extends through elevating assembly structure

62

, through rotating assembly

52

and through fixed support

51

thereby locking the control against both elevating and rotating motions. It may be possible to eliminate the portion of rotating assembly

52

from the above locking means since locking elevating assembly

62

directly to fixed support

51

will lock out both elevating and rotating motions.

As a secondary safety backup power supply switch

89

is mounted on bracket

75

on rotating assembly

62

such that it is contacted and operated by lock lever

86

when in the locked position shown in FIG.

2

. Switch

89

is a normally open switch and is closed by lock lever

86

as shown in FIG.

2

.

The purpose of switch

89

is to prevent activation of the primary power supply at the beginning of use of the aerial platform unless the analog control is in the neutral and locked position shown in FIG.

2

. Disabling initiation of the primary power supply may be accomplished, for instance, by disabling the starter circuit of an internal combustion engine, or by disabling the primary relay of an electrically powered aerial platform. When lock pin

88

is fully engaged as shown in

FIG. 2

it provides visual confirmation that the analog control is locked in neutral. Lock lever

86

is pivotally mounted on bracket

90

which is a part of elevating assembly

62

. This attachment may be divided, i.e., a two prong type to permit clearance from the portions of rotating assembly

52

and fixed support

51

when the elevating assembly

62

is lowered to cause lowering of the platform. Bellcrank

84

is pivoted on bracket

85

which is a part of tube

66

with slots in beam

65

for clearance and sliding of tube

66

.

Drive switch

68

is mounted on bracket

91

which is attached to beam

65

. Also attached to bracket

91

is link

92

which operates lift switch

93

. Lift switch

93

is mounted on bracket

76

which is part of rotating assembly

52

; thereby, lift switch

93

is not elevated when elevating assembly

62

is raised but is operated by link

92

attached to bracket

91

and beam

65

.

It is to be understood that ramps or guides will be provided as necessary to ensure that lock pin

88

and lock pin

72

are guided smoothly into their respective locked positions when handle

67

is released at a position other than the neutral position shown in FIG.

2

. Both safety lever

70

and lock lever

86

are spring loaded to return to the locked position. Likewise, although not shown for clarity, the mechanisms for the three primary controls are spring loaded to return to the neutral and locked position shown.

Elevating assembly

62

and its components are shaped to have a generally rectangular shape in the plan view so as to simulate a typical aerial platform with a vertically adjustable platform. This simulation may be enhanced by a decal or other means of embellishment on the sides of the elevating assembly

62

to more realistically resemble the aerial platform.

The embodiment shown in

FIG. 2

provides motion of the aerial platform analogous to the motion the operator imparts to the analog control. When the operator raises the control handle the platform is raised; when the operator pushes the control handle forward the aerial platform is driven forward; when the operator points the control to the right the machine (if driving forward) is steered to the right.

Another embodiment of the present invention is shown in FIG.

3

. This embodiment is an analog control for an aerial platform having a rotating turntable or turret on which a two-piece articulating boom is supported with an operator's platform attached to the upper end of the upper boom. The turntable may be mounted on a commercial truck chassis (see Type 1) or on a self-propelled chassis (see Type 2). The embodiment shown in

FIG. 3

is designed for a machine having two articulating booms but can be designed for an aerial platform having only one such boom, and, within limitations, for an aerial platform having more than two booms.

The analog control in

FIG. 3

includes fixed support

101

which is rigidly attached to structure at the operator's station on the platform such that the right end of the control is toward the front end of the aerial platform. Rotating assembly

102

is attached to fixed support

101

via bolt

104

and a suitable bearing

103

to permit easy rotation. Lower boom

106

is attached to two flanges

105

which are a part of rotating assembly

102

. Lower boom

106

is comprised of two plates that enter into the rotating assembly

102

and are jointed at the left end by lockplate

107

. Outside the rotating assembly

102

lower boom

106

may be a closed box or other configuration to resist torque which may be caused by a side load on handle

108

.

Located on the far side of lower boom

106

is rib

110

on which upper boom switch

111

is supported. In that location its operation will not interfere with power supply switch

112

which is located between the two plates comprising lower boom

106

and is attached to one of the plates. Likewise, lower boom switch

113

is supported on the rotating assembly

102

on the near side of the two lower boom plates and is operated by link

114

which is attached to lower boom

106

via pin

115

.

Rotating control switch

116

is attached to the under side of rotating assembly

102

and is operated by contact of roller

118

with bracket

117

when assembly

102

is rotated. An equivalent bracket is located on the near side of roller

118

to operate switch

116

when assembly

102

is rotated in the other direction. Upper boom tube

120

which is pivoted on the upper end of lower boom

106

operates upper boom switch

111

through a hole in cover

122

which comprises the top surface of rotating assembly

102

. It can be seen that when handle

108

is raised to elevate upper boom tube

120

, link

121

will cause upper boom switch

111

to be operated sending the desired signal to the mechanism for elevating the upper boom of the aerial platform. When handle

108

is lowered, upper boom switch

111

will be operated in the opposite direction sending the signal to lower the upper boom. Likewise, pulling handle

108

to the left will cause lower boom

106

to rotate counterclockwise on its pivot on flanges

105

thereby causing link

114

to operate lower boom switch

113

sending the signal to the mechanism for raising the lower boom of the aerial platform. Pushing handle

108

to the right will cause lower boom switch

113

to be operated in the opposite direction thereby sending the signal to lower the lower boom of the aerial platform.

The primary purpose of channel

119

attached to the right end of upper boom tube

120

is to more completely simulate the appearance of a typical aerial platform having two articulating booms. Additional features

123

may be added to channel

119

by decals or by shaping to give the appearance of the particular model of serial platform on which the analog control is to be used. Similarly, simulated platform

124

, mounted on handle

108

and boom tube

120

, may be shaped to appear like a fiberglass bucket typically used on aerial platforms for utility line maintenance or it may be shaped to match the aerial platform on which the control is to be used.

Handle

108

is inserted into and attached to the left end of upper boom tube

120

. Safety lever

125

is pivotally attached at its upper end to handle

108

and is operated by the operator when he grasps handle

108

to operate the control. As the safety lever

125

travels through its final motion it contacts operating pin

130

of safety switch

129

and causes the primary controls to be operational in compliance with the requirements of the industry standards. Hence, the first motion in releasing the safety lever

125

will cause the primary controls to be deactivated and all powered motion of the aerial platform to stop. To that end slot

131

is provided in safety lever

125

where link

126

is connected so that safety switch

129

will be released even if link

126

has not returned to the neutral and locked position shown in FIG.

3

.

When safety lever

125

is pulled toward handle

108

, link

126

operates lock lever

127

which rotates about its pivot

109

on upper boom tube

120

. Thereby lock pin

128

is withdrawn from the locked position shown in

FIG. 3

when safety lever

125

is operated, and the control is then free to operate in any and all of the three primary motions it controls. It will be noted that in the locked position, lock pin

128

prevents raising of the upper boom tube

120

via lock lever

127

, prevents movement of lower boom

106

via lockplate

107

and prevents rotation by engaging rotating assembly

102

. It is to be understood that upper boom tube

120

, lower boom

106

and rotating assembly

102

are all spring loaded to the neutral position shown in FIG.

3

. Likewise, safety lever

125

and lock lever

127

are spring loaded to return to the locked position shown.

The tip of lock pin

128

also contacts and operates power supply switch

112

which prevents activation of the primary power supply of the aerial platform unless the analog control is in neutral and locked as shown in FIG.

3

. The tip of lock pin

128

has a smooth rounded surface to permit guiding it back into the holes without impediment. Also shown in

FIG. 3

is enable switch

133

, of which two or more may be provided for auxiliary functions as may be appropriate for a specific configuration aerial platform.

In summary of embodiment

3

shown in

FIG. 3

it can be seen that 1) raising the handle causes analogous motion of the upper boom of the aerial platform, 2) pulling on handle

108

causes lower boom

106

and the lower boom of the aerial platform to be raised, and 3) rotating the analog control via handle

108

causes analogous rotation of the turntable of the aerial platform.

FIGS.

1

-

3

depict analog controls suitable for three of the most numerous configurations of aerial platforms; however, an analog control can be tailored for most configurations. For instance, an aerial platform having two articulating booms of which the upper boom also can telescope may be equipped with an analog control having some of the elements of the embodiment illustrated in FIG.

3

and some of the embodiment illustrated in FIG.

1

. One approach immediately evident is to use the embodiment illustrated in

FIG. 3

with one enable switch

133

to substitute upper boom telescope for the lower boom lift function. Then, by pulling on handle

108

the operator would cause the boom to extend out and by pushing on handle

108

he would cause the boom to retract; both motions of the control are analogous to the boom motions which result.

With respect to selection of specific mechanisms to simulate motions that are analogous to those of an aerial platform, many variations are possible. One preferred embodiment of the apparatus illustrated in

FIG. 2

is to simulate driving by placing the control including the fixed support

51

on an interlocking track or slides with appropriate rollers, stops, spring loading and switch location. This would replace the complexities inherent in the telescoping control (inner tube

66

and beam

65

) plus the bellcrank

84

and link

85

needed to accommodate that motion.

Another potential application for an interlocking track or slides in the embodiment illustrated in

FIG. 2

is to replace with vertical slides the four parallel links

58

,

59

and

60

, which simulate elevating while controlling the attitude of elevating assembly

62

. Similarly, the internal locking detailed in FIG.

2

and described above, may be adapted to be used in the embodiments illustrated in

FIGS. 1 and 3

.

Another embodiment of the analog control of the present invention is shown in FIG.

4

and defines an approach using tracks and sliding motion for both vertical and horizontal motion which is well suited to the Type 3 aerial platform, as discussed above with reference to

FIG. 2

, although the elements may be used on controls for other type aerial platforms. In

FIG. 4

fixed structure

151

is attached to structure at the operator's station on the platform. Rotating structure

152

is attached to fixed structure

151

by bolt

156

and can be rotated on bearing

155

. Steer switch

161

is shown in phantom attached to the lower side of rotating structure

152

. When rotating structure

151

is rotated, steer switch

161

is operated by contact of wheel

162

on clip

163

which is attached to fixed structure

151

. An equivalent clip contacts the other side of wheel

162

when rotating structure

151

is rotated in the opposite direction.

Rollers for horizontal motion are indicated by rollers

159

and

160

, two at each end of rotating structure

152

. Horizontal track

167

is engaged to roll on and be constrained by rollers

159

and

160

to simulate motions analogous to driving the aerial platform forward or rearward. The rollers

159

and

160

have a shoulder

186

to resist lateral forces in the horizontal plane between rotating structure

152

and track

167

. Attached to the vertical flanges of horizontal tracks

167

are brackets

169

(one on the vertical flange of each horizontal track

167

). On one bracket

169

the drive control switch

181

is attached. Shown in phantom is lift control switch

182

which is attached to the side of the other bracket

169

such that the space between the switches is open for clearance from the locking and unlocking mechanism. Attached to bracket

169

on the same side as drive control switch

181

is power supply switch

191

as described in embodiment No. 2.

Also attached to the horizontal flanges of horizontal tracks

167

is horizontal pan

187

which has a suitable opening

190

for clearance from parts attached to rotating structure

152

. Post

189

is anchored in rotating structure

152

and operates drive control switch

181

via link

185

as the control assembly attached to horizontal tracks

167

is moved to the left or to the right in FIG.

4

. Lift control switch

182

is operated by link

183

which is pivotally attached to clip

184

which in turn is attached to cover

179

. Cover

179

moves up or down as handgrip

172

is operated to raise or lower the platform of the aerial platform. Cover

179

is attached to vertical tracks

154

and encloses the mechanism on the top, both sides and the end opposite vertical tracks

154

.

Vertical roller support

168

is attached to pan

187

and to both brackets

169

to form a rigid structure along with horizontal tracks

167

. Vertical roller support

168

provides support for two sets of rollers,

164

and

165

in one plane and two sets of rollers,

166

and

188

in the plane at ninety degrees, to restrain vertical roller support

168

against forces in any potential direction except vertical. Vertical track

154

is engaged with the four pairs of rollers,

164

,

165

,

166

and

188

, and is thereby constrained against any forces except vertical with respect to vertical roller support

168

; see FIG.

4

B.

The control in

FIG. 4

is operated by handgrip

172

which is attached to vertical tracks

154

and cover

179

by bracket

170

. Safety switch

194

is located in handgrip

172

as in the other embodiments except that it is shown in

FIG. 4

with the operating pin recessed within handgrip

172

so as to minimize the likelihood of safety switch

194

being operated inadvertently or defeated deliberately. In this embodiment safety switch

194

is operated by a properly located pin within safety lever

171

such that the final travel of safety lever

171

as it is pulled by the operator causes the pin to contact the operating pin of safety switch

194

.

When safety lever

171

is pulled, it causes link

173

to operate bellcrank

174

in a counterclockwise direction. Bellcrank

174

includes a trunnion

175

which is pivoted between the two brackets

169

. Link

173

passes through slots in vertical tracks

154

and in vertical roller support

168

. As the bellcrank

174

is rotated, it pulls link

176

and withdraws drive lockpin

177

from its engagement with fixed structure

151

. Lockpin

177

also passes through spacer

193

which is attached to cross member

178

and thereby to horizontal tracks

167

. Cross member

178

is also attached to pan

187

and thereby to vertical roller support

168

. When drive lockpin

177

is withdrawn from fixed structure

151

, it also permits rotation of the rotating structure

152

and the horizontal tracks

167

with items attached thereto so that rotation will cause steer switch

161

to be operated.

Counterclockwise rotation of bellcrank

174

also pulls link

180

and withdraws lift lockpin

153

from its hole in vertical tracks

154

, thereby permitting vertical tracks

154

and attached cover

179

to be raised or lowered to operate lift switch

182

. Thus, operating safety lever

171