The present exemplary embodiment relates to telescoping masts. It finds particular application in conjunction with pneumatically actuated telescoping masts, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
Pneumatically actuated telescoping masts are well known in the art, and are, for example, mounted on the roof of a motor vehicle such as an emergency vehicle or utility vehicle. Alternatively, mounting configurations may also involve the floor of a vehicle, allowing the telescoping mast to extend through the roof of the vehicle. The mast is generally used for positioning electrical devices, such as lighting fixtures, at an elevated point above the vehicle. The effect of a lighting fixture is to light a large area around the vehicle, thus allowing emergency procedures to be conducted under the light, such as at accident scenes or by utility work crews during power outages, for example. Pneumatically actuated telescoping masts are particularly advantageous for such uses, because they are lightweight, compact in the retracted position, and quickly transportable to a site by the vehicles on which they are mounted. Pneumatically actuated telescoping masts are extended and retracted using air under pressure and, in a fully extended use position, are usually vertical, although they can be inclined in the use position. The vehicle on which the telescoping mast is mounted typically includes a compressor and appropriate pneumatic controls for displacing the mast sections between retracted and extended positions.
In a typical mast, each telescoping section includes a hollow cylindrical body with a collar secured to an end thereof. The collar can include a keyway (or key) for rotationally interlocking the telescoping section with an adjacent telescoping section or sections. The collar can also provide reinforcement to the cylindrical body.
Many prior art masts utilize a collar at the top of each telescoping section that extends radially outwardly from the cylindrical body. Such collars are often bolted or otherwise secured to the cylindrical body of the telescoping section. This allows an adjacent (smaller diameter) cylindrical body of an adjacent connected telescoping section to be retracted into the larger diameter telescoping section. In this manner, each telescoping section can be retracted into the next larger telescoping section. It will be appreciated, however, that the collars limit the longitudinal extent to which a particular telescoping section can be retracted. That is, the radially-outwardly extending collar of the telescoping section being retracted will ultimately interfere with the collar of the telescoping section into which it is being retracted, thereby limiting further retraction. Accordingly, in a fully retracted state, such masts have a height that is generally determined by a length of the base telescoping section, and the combined height of each collar of each additional telescoping section of the mast.
For example,
Commonly assigned U.S. Pat. Nos. 6,290,377; 5,980,070; 5,743,635; 6,299,336; and 6,767,115 are each incorporated by reference herein so that pneumatically actuated telescoping masts known in the art need not be described in detail hereinafter.
While the above-described mast assembly has been commercially successful, recent changes in vehicle designs have produced a need for an improved telescoping mast. For example, in an effort to increase efficiency, vehicles have become more streamlined and, in some cases, smaller, which has altered the available area for mounting a mast. As such, it has become desirable to provide a mast with a lower profile when stowed, but that also achieves the same or similar extended length as a conventional.
In accordance with one aspect of the present exemplary embodiment, a telescoping mast assembly having a mast axis comprises a plurality of telescoping mast sections having axially opposite ends and being axially slidable relative to one another along the mast axis between retracted and extended positions, the telescoping mast sections including a base tube adapted to be fixed to a support surface and an innermost telescoping section, and wherein the innermost telescoping section supports a cylindrical can adapted to surround at least a portion of an axial end of the base tube when the mast assembly is in the retracted position is provided.
In one embodiment, the can includes a cavity defined by a circular top wall and a cylindrical side wall extending from an edge of the top wall, the cavity having an inner diameter sized to closely receive the axial end of the base tube. The base tube includes a projection on a circumferentially outer surface thereof, and the side wall of the can includes an opening adapted to receive the projection when the mast assembly is in the retracted position thereby rotationally interlocking the innermost tube section and the base tube. The protrusion and opening are wedge-shaped. The protrusion is secured to the base tube with a fastener. The protrusion is adjacent an axial end of the base tube. Each telescoping mast section can include an internal collar and a cylindrical body. The internal collar can include an annular body adapted to be inserted into an open end of the cylindrical body, the internal collar having a radially outwardly extending shoulder adapted to engage an axial end face of the cylindrical body. A circumference of the internal collar can correspond to a circumference of the cylindrical body. The internal collar can be secured to the cylindrical body with at least one fastener, such as a machine screw. Each telescoping mast section starting with the innermost telescoping mast section can have a maximum outer diameter that is smaller than the inner diameter of an axial end opening of the telescoping mast section into which it is received.
In accordance with another aspect, a method of rotationally interlocking a plurality of telescoping mast sections of a mast assembly comprises interlocking a can member supported by an innermost telescoping mast section with a base tube of the mast assembly. The interlocking can include telescoping an open end of the can member over an axial end of the base tube when the mast assembly is in a retracted position. The method can include providing a protrusion on a circumferentially outer surface of the base tube, the protrusion adapted to cooperate with an opening of the can member to restrict relative rotation therebetween is provided.
In accordance with yet another aspect, a telescoping mast assembly having a mast axis and comprising a plurality of telescoping mast sections having axially opposite ends and being axially slidable relative to one another along the mast axis between retracted and extended positions, the telescoping mast sections including a base tube adapted to be fixed to a support surface and an innermost telescoping section, and wherein the innermost telescoping section supports a cylindrical nest lock platform assembly adapted to cover an axial end of the base tube when the mast assembly is in the retracted position, wherein each telescoping mast section includes an internal collar and a cylindrical body and the nest lock platform assembly includes a payload platform and one or more wedges that mate with corresponding notches in the internal collar is provided. Optionally, in accordance with any of the previous embodiments, a circumference of the internal collar corresponds to a circumference of the cylindrical body. Additionally, in accordance with any of the previous embodiments, the internal collar may be secured to the cylindrical body with at least one fastener. In accordance with any of the previous embodiments, the at least one fastener may include a machine screw. In accordance with any of the previous embodiments, each telescoping mast section starting with the innermost telescoping mast section may have a maximum outer diameter that is smaller than the inner diameter of an axial end opening of the telescoping mast section into which it is received.
Referring to the remainder of the drawings, wherein the showings are for the purpose of illustrating preferred embodiments of the invention only and are not for the purpose of limiting same,
With additional reference to
As shown in
Each internal collar 130 has opposed keyways 142 for receiving keys 143 (see
In
With further reference to
Returning to
Turning to
It will be appreciated that, when the mast assembly 100 is fully retracted, the side walls 160 of the slot 156 engage opposed sides of the nest lock member 150 thereby restricting rotation of the can 146. Because the can is fixed to the innermost tube and all of the tubes are keyed together, each of the tube sections is locked against relative rotation therebetween. The base wall 158 of the slot 156 can abut the top of the nest lock member 150 and, in some embodiments, act as a stop for restricting further retraction of the mast assembly 100.
In some embodiments, the nest lock member 150 and the slot 156 can have other shapes. In addition, while the illustrated embodiment includes two nest lock members 150 spaced approximately opposite each other (see
It should now be appreciated that the internal collars 130 facilitate a low profile nested configuration such that the can 146 has a relatively short axial extent while still covering all of the telescoping mast sections and partially surrounding the base tube 118. By minimizing the axial extent of the can 146, the weight of the can 146 is minimized, thereby maximizing the mast payload. In one embodiment, a mast with a 50-foot extended height includes a can 146 with an axial length of less than 3 inches (e.g., 2.875 inches).
In addition to rotationally interlocking the telescoping mast sections, the can 146 also provides protection from the elements and reduces ingress of moisture and/or contaminants when the mast assembly 100 is in a stowed (retracted) configuration. Accordingly, a suitable sealing element or gasket can be provided for sealing between the can 146 and the base tube (not shown). The can 146 also provides an enlarged surface for securing a payload, such as lighting fixtures and other types of electrical devices.
An alternative embodiment of the nest lock system, i.e., a platform and collar nest lock system 200, for use with the mast sections 102, 104, 106, 108, 110, 112, 114, 116 and the base section 118 is shown in
With reference to
When the nest lock platform assembly 210 engages the internal collar 212, the wedges 216 of the nest lock platform assembly mate with the notches 220 of the internal collar. This mating process helps to eliminate rotational slop between the top tube (not shown) and its mating tube (not shown). The nest lock platform assembly 210 mounts to the top tube stub, which mounts to the top tube. The nest lock platform assembly 210 mounts to the mast in generally the same way as the can-style nest lock system as described above.
With additional reference to
As shown in
The platform and collar nest lock system 200, including the nest lock platform assembly 210, the payload platform 214, and the wedges 216, is shown in greater detail in
The O-ring cord 226 is adhered into a groove around the bottom side of the payload platform 214. The O-ring cord 226 seals off the mast and thus prevents debris and water from getting inside when the mast is completely nested. Optionally, in accordance with any of the previous embodiments, the O-ring cord 226 could be replaced by a rubber pad, which would cover the entire bottom face of the nest lock platform assembly 210. The wedges 216 are held in place by the pins 224 and a dovetail feature on the sides of the payload platform 214. The roll pins 224 are press-fit into the payload platform 214 and float freely inside of the wedges 216 through holes (not shown). This allows the wedges 216 to move freely along the axial direction of the roll pins 224 (i.e., up and down). The rubber bumpers 222 are located between the dovetail ceilings of the payload platform 214 and the top of the wedges 216. It is to be understood that the rubber bumpers 222 could be rubber pads, springs, Belleville washers, or anything of that nature. The rubber bumpers 222 generally function as springs and compress when the wedges 216 engage the notches 220 of the internal collars 218. This allows the wedges 216 to be “self-adjusting.” In some embodiments, the wedges 216 and the notches 220 can have other shapes. In addition, while the illustrated embodiment includes two wedges 216 spaced approximately opposite each other (see
With reference to
It is noted that the internal collar on the outer most tube is engaged with the nest lock platform assembly. All other tubes are staggered below the outer most collar.
It should now be appreciated that the exemplary mast of the present disclosure typically has a shorter nested height as compared to prior art masts of the same extended length. In addition, both the can style nest lock system and the platform and collar nest lock system may provide both rotational interlocking of the telescoping mast sections as well as protection from the elements.
The exemplary embodiment has been described with reference to the preferred embodiments. Modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
This application claims the benefit of U.S. Provisional Application No. 62/146,087, filed Apr. 10, 2015, incorporated herein by reference in its entirety.
Number | Date | Country | |
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62146087 | Apr 2015 | US |