Title:
Aerial ladder truck
United States Patent 3921758


Abstract:
There is provided an aerial ladder truck having suitable means whereby obstacles such as ice and snow to the rolling movement of the ladder extending and contracting rollers and lifter raising and lowering rollers on ladder guide rails are scraped off as the unit ladders are extended and contracted and the lifter is raised and lowered.



Inventors:
KOZAI TETSUO
Application Number:
05/501190
Publication Date:
11/25/1975
Filing Date:
08/27/1974
Assignee:
MORITA FIRE PUMP MFG. CO., LTD.
Primary Class:
Other Classes:
182/103, 182/127, 182/129
International Classes:
E06C5/04; (IPC1-7): E06C5/04
Field of Search:
182/127,129,64-68,203,207,208,209,210,211,103,102 104
View Patent Images:
US Patent References:
2614743Turntable control means for aerial ladders1952-10-21Arps
1372212Rail-cleaning machine1921-03-22Wettervik



Primary Examiner:
Machado, Reinaldo P.
Attorney, Agent or Firm:
Hall & Houghton
Claims:
What is claimed is

1. In an aerial truck assembly to be mounted on the rear of a fire truck including a first elongated channel shaped ladder unit having laterally spaced, longitudinally extending guide rail means along its top thereof and having means at one end for mounting same to a fire truck, a plurality of additional and separable elongated channel shaped ladder units, each unit having spaced guide rail means along the top thereof, each of said additional ladder units positioned within said first ladder unit and within one another in nesting relationship, each succeeding ladder unit being of a width less than the width of the preceding ladder unit, each of said plurality of ladder units being extendable from and retractable within one another, and roller means positioned between the mating surfaces of each said guide rail means of each of said interfitted ladder units to permit easy relative movement between each ladder unit, the improvement of means for removing snow, ice and the like from the longitudinally extending guide rail means of each of said ladder units, said snow and ice removal means comprising scraper means mounted in operative relationship with each of said ladder units adjacent each of said roller means and on opposite sides thereof for engaging the surface of the respective guide rail means of each of said ladder units during the extending and the retraction of each of said ladder units with respect to one another.

2. In a ladder assembly as called for in claim 1, wherein the ladder further includes a lifter comprising elongated frame means of a width less than the width of the innermost ladder, transverse frame means mounted adjacent the front and rear ends of said elongated frame means and being of a length sufficient to span the lateral distance between the spaced rail means of the first ladder unit, roller shaft means mounted in operative relationship between the outside ends of each of the transverse frame means, roller means mounted on said roller shaft means for engagement with the elongated rail means of the ladder units during the stepwise extension of one ladder unit from another, and means to move the lifter for the extension or retraction of the ladder units with respect to one another, and the snow and ice removal means comprising scraper means mounted on each end of each of said transverse frame means, said scraper means extending over each of said roller means and on opposite sides thereof to engage the elongated rail means of each of said ladder units during the extending and the retraction of each of said ladder units with respect to one another.

3. In an aerial ladder truck assembly to be mounted on the rear of a fire truck including a first ladder section having a rectangular channel shaped, cross-section configuration forming longitudinally extending, laterally spaced guide rail means, a second ladder section having a rectangular channel shaped, cross-section configuration forming longitudinally extending laterally spaced guide rail means therealong, said second ladder section being of a width less than that of the first ladder section and positioned in nesting relationship within the channel shaped configuration of said first ladder section, roller means positioned between the mating surfaces of the respective guide rail means of the first ladder section and the guide rail means of the second ladder section to permit the longitudinal withdrawal of said second ladder section from said first ladder section, at least one more ladder section having a rectangular channel shaped configuration forming longitudinally extending, laterally spaced guide rail means therealong, said at least one more ladder section being of a width less than that of said second ladder section and being positioned in nesting relationship within the channel shaped configuration of said second ladder section and roller means positioned between the mating surfaces of the respective guide rail means of said second ladder section and said at least one more ladder section to permit the longitudinal withdrawal of said at least one more ladder section from said second ladder section, and means for extending and retracting said second ladder section from said first ladder section and at least the one other ladder section from the second ladder section and from one another, the improvement of means for removing snow, ice and the like from the longitudinally extending guide rail means of each of said ladder sections, said removal means comprising scraper means mounted on each said ladder section on opposite sides of each of said roller means thereof for engaging the surface of the respective guide rail means of each of said ladder sections during the extending and the retraction of each of said ladder sections with respect to one another.

Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an aerial ladder truck of the type having a lifter used for fire fighting and other high-altitude operations.

2. Description of the Prior Art

In aerial ladder trucks, a known aerial ladder assembly comprises extending and contracting rollers attached to one unit ladder where unit ladders are fitted together, so that said rollers roll on guide rails provided on the other unit ladder when the ladders are extended and contracted. Further, the lifter in which the operator rides has lifter raising and lowering rollers attached to the bottom surface thereof which roll on lifter guide rails on the upper surfaces of the unit ladders when the lifter is raised and lowered. With this arrangement, however, during use of the aerial ladder assembly in a cold district or in winter, water discharged for fire fighting falls in drops from the topmost end of the erected ladder assembly along the guide rails on the unit ladders and eventually the freezing of water takes place, forming layers of ice on the rail surfaces. Further, snow may lie on the rail surfaces. Such ice and snow form obstacles to the rolling movement of the rollers, interfering with smooth and safe operation of the ladder and lifter, and in extreme cases operation becomes impossible.

SUMMARY OF THE INVENTION

The present invention provides an aerial ladder truck comprising scrapers provided forwardly of the extending and contracting roller attachment regions of one unit ladder where unit ladders are fitted together, for scraping off obstacles such as ice and snow on guide rails on the other unit ladder on which the rollers roll, and scrapers provided forwardly of the lifter raising and lowering roller attachment regions of a lifter mounted on the upper surface of the aerial ladder assembly, for scraping off ice and snow on the rails on the unit ladders on which the rollers roll.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings showing a preferred embodiment of the present invention:

FIG. 1 is a side view of an aerial ladder truck;

FIG. 2 is an enlarged side view of extending and contracting roller attachment regions of unit ladders;

FIG. 3 is a section taken along the line III -- III in FIG. 2;

FIG. 4 is a section taken along the line IV -- IV in FIG. 2;

FIG. 5 is a perspective view showing a scraper attachment region in the side wall of a unit ladder;

FIG. 6 is a perspective view of a lifter mounted on a ladder assembly;

FIG. 7 is an enlarged section showing roller mounting regions of the lifter and unit ladders; and

FIG. 8 is a section taken along the line VIII -- VIII in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIG. 1, a ladder assembly 1 is of the tiltable type including a first stage ladder 1a having a support member 5 at its base portion pivotally mounted on a pivot 6 carried by a frame 4 attached to a turntable 3 mounted on the rear portion of a truck chassis 2. As shown in FIGS. 2-4, the first stage ladder 1 has a rectangular channel-shaped cross-section and receives the second stage ladder 1b which is smaller in size. Bottom rollers 7L, 7R, lateral rollers 8L and 8R are rotatably mounted on both sides on the inner bottom surface at the front end portion of the first stage ladder 1a. Traveling rollers 9L and 9R and float preventing rollers 10L and 10R are mounted one above the other on both outer lateral surfaces at the rear portion of the second stage ladder 1b. When the second stage ladder 1b is extended and contracted, the rollers 9L, 10L and 9R, 10R carried thereon roll on guide rails 11L, 12L and 11R, 12R positioned one above the other on the opposite lateral plates of the first stage ladder 1a and projecting from and extending longitudinally of the first stage ladder. Concurrently therewith, the guide rail portions 1f and 1g on both sides on the bottom surface of the second stage ladder 1b are guided and supported by the rollers 7L, 8L and 7R, 8R so that the second stage ladder is smoothly extended and contracted with respect to the first stage unit ladder 1a. The third, fourth and fifth stage unit ladders 1c, 1d and 1e have rectangular channel-shaped cross-sections which become successively smaller in size, and they are fitted together and extending and contracting rollers are provided on one unit ladder where they are fitted together while guide rails are provided on the other unit ladder, in the manner described above, thereby ensuring smooth and quiet exension and contraction operation with decreased frictional resistance. A water discharging gun 13 is mounted on the front end of the topmost ladder 1e for fire fighting operation with water supplied through a hose extending thereto from the truck chassis 2. Since water falls in drops along the guide rails of the unit ladders, ice forms on the rail surfaces if the aerial ladder truck is used in a cold district or in winter. If a layer of ice or snow exists on the upper and lower guide rails 12L, 11L and 12R, 11R on which the rollers 10L, 9L and 10R, 9R roll, this will interfere with smooth rolling of the rollers. Since the distance between the upper and lower rollers is constant, there is the danger that extension and contraction operation becomes impossible. In order to overcome this difficulty, scrapers 14a, 14b and 14c, 14d are provided as shown in FIG. 5 forwardly of the upper and lower rollers 10R and 9R on the outer lateral surface of the second stage ladder 1b, that is they are spaced from each other in the direction of rolling movement of the rollers and positioned on both sides of each roller 10R, 9R. The scrapers are formed of a metal plate in an L-shape with a width corresponding to the roller width, having reinforcing plates 15a, 15b and 15c, 15d secured inside the corners thereof. Brackets 17a, 17b and 17c, 17d are attached to and project from the lateral plate 16 of the second stage ladder 1b with the rollers 10R, 9R therebetween. The vertical portions of the scrapers are secured to said brackets and their horizontal portions are directed in the direction of rolling movement of the rollers and positioned parallel and adjacent to the guide rail surfaces, with their front ends being in the form of knife edges having a suitable scraping angle with respect to said surfaces. The characters 18 and 19 designate roller shafts. Further, such scrapers are also provided on the second stage ladder 1b which are spaced from each other and positioned on both sides of the rollers 9L and 10L in opposed relation to the guide rails 11L and 12L, in the manner described above. If necessary, similar scrapers may be provided for the rollers 7L, 7L and 8R, 8R at the front end of the first stage ladder 1a in closely adjacent ralation thereto and attached to the member to which the rollers are attached. Further, scrapers are provided forwardly of the extending and contracting roller attachment regions of one unit ladder where the third, fourth and fifth stage unit ladders 1c, 1d and 1e are fitted together, in closely adjacent relation to the guide rail surfaces on the other unit ladder on which said rollers roll, in the manner described above.

When the aerial ladder assembly 1 is extended and contracted by known means, the scrapers 14a, 14b and 14c, 14d located forwardly of the rollers 10R and 9R on the rear portion of the second stage ladder 1b are moved along the lower surface of the upper guide rail 12R and the upper surface of the lower guide rail 11R. As a result, if there are obstacles A such as layers of ice and snow located on the rails forwardly in the direction of rolling movement of the rollers, they are scraped off and laterally dischaged by the scrapers in advance of the rolling movement of the rollers. In the case where there are obstacles on the rail surfaces where other unit ladders are fitted together and the rollers roll thereon and in the case where the guide rails move on the rollers, the obstacles are scraped off and laterally discharged by the scrapers in advance of such movement.

In FIG. 6, the character 20 designates a lifter adapted to be raised and lowered along the upper surface of the aerial ladder assembly 1; 21, the frame thereof; 22, a collapsible handrail; 23, a step; 24, a brake cover; and the character 25 designates a safety belt. Transverse frames 26 at the front and rear of the frame 21 have their opposite ends outwardly extended until they lie over the guide rails 27L and 27R on the opposite lateral upper surfaces of the unit ladders 1a, 1b, 1c, and 1d which are flush with each other. As shown in FIG. 7, on a roller shaft 28 journaled between the opposite lateral plates 26a and 26b of the transverse frame 26, raising and lowering rollers 29L and 29R are mounted in opposed guide rails 27L and 27R so that these rollers ride on the corresponding rails. Between the opposite lateral plates 26a, 26b and the guide rails 27L, 27R, arm plates 30L and 30R project downwardly from the frame 26 and carry clamping auxiliary rollers 31L and 31R abutting against the lower surfaces of the rails. With the aerial ladder assembly in its extended position, when the lifter 20 is moved from the first stage ladder 1a to the fifth stage ladder 1e by known means, each time the lifter changes from one ladder stage to another the rolling of the outermost rollers 29L, 31L and 29R, 31R on the rails changes over to that of the successive inwardly located rollers on their associated rails. In this manner, the lifter is raised. Conversely, when the lifter is lowered, each time the lifter changes from one ladder stage to another the rolling of the innermost rollers on the associated rails changes over to that of the successive outwardly located rollers on their associated rails. In this manner, the lifter is lowered. If there are obstacles A such as layers of ice and snow on these rails, they interfere with smooth rolling of the rollers. Further, since the clamping distance between the upper and lower rollers 29L, 29R and 31L, 31R is constant, there is the possibility that the raising or lowering of the lifter becomes impossible. In order to overcome this difficulty, scrapers 32L and 32R are provided as shown in FIGS. 6-8 forwardly of the series of raising and lowering rollers 29L and 29R on the transverse frame 26, that is, they are spaced from each other in the direction of rolling movement of the rollers and positioned on both sides of the rollers. The scrapers 32L and 32R are formed of a metal plate in a band plate shape covering the front and back and right and left sides of each roller series at the opposite end portions 26L and 26R, and they are fixed to the frame top at their upper edge bends and at right angles to the rails 27L and 27R and at a suitable scraping angle with respect to the rail surfaces, with their front edges being in the form of knife edges.

When the lifter 20 is raised or lowered along the aerial ladder assembly 1, the scrapers 32L and 32R located forwardly of the respective series of raising and lowering guide rails 29L and 29R move on the upper surfaces of the guide rails 27L and 27R. If, therefore, there are obstacles A such as layers of ice and snow on the rails forwardly as viewed in the direction of rolling movement of the rollers, they are scraped off and laterally dischaged by the scrapers 32L and 32R in advance of the rolling movement of the rollers. In addition, scrapers may be attached to the roller attaching members and spaced from each other in the direction of rolling movement of the rollers and positioned on both sides of the rollers 31L and 31R so that they may scrape off obstacles on the rail surfaces. Further, since obstacles on the rails are scraped off by the outside scrapers carried by the front and rear transverse frames 26 when the lifter is raised and lowered, the inner scrapers may be omitted.

Whiles there have been described herein what are at present considered preferred embodiments of the several features of the invention, it will be obvious to those skilled in the art that modifications and changes may be made without departing from the essence of the invention.

It is therefore to be understood that the exemplary embodiments thereof are illustrative and not restrictive of the invention, the scope of which is defined in the appended claims and that all modifications that come within the meaning and range of equivalency of the claims are intended to be included therein.