Driven Handrail Means For Escalators

Abstract

An escalator having transparent balustrades and driven handrail means in which a handrail shaft is immediately adjacent the shaft which carries the driven sprockets for the step chains and is provided with drive sprockets that are directly engaged by the step chains so as to be driven by the latter. Handrails are guided beneath sheaves that are fixedly mounted on the drive sprockets, and guide roller sets support the handrails and maintain them in driving engagement with the bottoms of the sheaves. In an area remote from the handrail shaft are handrail tensioning means including a self-adjusting tensioning sheave mounting.

Description

BACKGROUND OF THE INVENTION

One of the relatively recent escalator developments is escalators having transparent balustrades which harmonize with modern building architecture. Such escalator structures require novel means for guiding and driving the moving handrails, because the entire handrail drive must be mounted below the moving stairway where it may be concealed by the escalator sideplates that conceal the frame, the step chain sprockets, the return runs of the step chains and steps, and the drive mechanism. Various mechanisms for driving the handrails of transparent balustrade escalators are disclosed in U.S. Pat. Nos. 3,049,213, (Re. 25,531), 3,170,557 and 3,283,878.

The present invention comprises an improved and simplified driven handrail means for escalators which is particularly applicable to escalators having transparent balustrades. In addition, the invention includes handrail tensioning means with a novel self-adjusting sheave mounting.

SUMMARY OF THE INVENTION

The principal object of the present invention is to provide improved driven handrail means for escalators in which the handrail drive is concealed beneath the moving stairway so the arrangement is particularly applicable to escalators having transparent balustrades.

In accordance with the invention a handrail shaft is mounted in the escalator frame immediately adjacent the shaft which carries the driven sprockets for the step chains, and drive sprockets on the handrail shaft are directly engaged by the step chains so as to be driven by the latter. The apparatus eliminates the separate belt drives or chain drives which have heretofore been employed in the prior art to drive the handrails.

Another object of the invention is to provide tensioning means for an escalator handrail in which a vertically movable tensioning sheave is supported on a carriage which permits the weight of the sheave to be carried in the return run of the handrail so the weight of the sheave tensions the handrail; and the carriage is provided with a unique anti-reverse arrangement so that the tensioning sheave is self-adjusting as the handrail stretches during use.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side elevational view of a transparent balustrade escalator embodying the present invention with parts of the escalator sideplate broken away for clarity;

FIG. 2 is a fragmentary sectional view illustrating details of the handrail drive and is taken substantially as indicated along the line 2--2 of FIG. 4;

FIG. 3 is a fragmentary section taken substantially as indicated along the line 3--3 of FIG. 4;

FIG. 4 is a transverse sectional view taken substantially as indicated along the line 4--4 of FIG. 1;

FIG. 5 is a fragmentary transverse section on an enlarged scale which is also taken substantially as indicated along the line 4--4 of FIG. 1 to afford more detailed disclosure of the handrail drive structure;

FIG. 6 is an enlarged fragmentary sectional view with parts broken away illustrating the handrail tensioning means and is taken substantially as indicated along the line 6--6 of FIG. 7; and

FIG. 7 is a fragmentary section on an enlarged scale taken substantially as indicated along the line 7--7 of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings in detail, and referring first to FIGS. 1 and 4, an escalator is provided with a frame, indicated generally at 10, which includes structural members 11 and sideplates 12, and has a lower end portion 13, an upper end portion 14, and an inclined portion 15. The lower end portion of the escalator is supported on building structural members S which carry the ceiling of a floor below that at which the lower end of the escalator is located, and the lower end portion of the escalator is entirely below the level of a floor F which is the lower floor served by the escalator. Similarly, the upper end portion 14 of the escalator frame is substantially entirely below the floor of the upper floor served by the escalator and supported upon the building structural members which carry the ceiling of the lower floor served by the escalator. For purposes of the present disclosure the frame 10 also includes cover plate means 16 which extends continuously from the lower end to the upper end of the frame to cover the mechanism which is at two sides of the escalator. The two cover plates 16 are surmounted by balustrades, indicated generally at 17, which include a transparent balustrade plate 18 the upper edges of which support handrail guides 19. The balustrades are seen to include arcuate lower ends 20, arcuate upper ends 21, and inclined portions 22; and the handrail guides 19 extend continuously around the arcuate portion 20, up the inclined portion 22, and around the arcuate portion 21.

Supported in the frame structural members 11 are a lower sprocket shaft 23 and an upper sprocket shaft 24 adjacent the ends of which are identical lower step chain sprockets 25 and upper step chain sprockets 26, respectively. The sprockets 25 and 26 include large grooves such as the grooves 25a, alternating with small grooves such as the grooves 25b. A pair of endless step roller chains 27 are trained above the lower and upper sprockets 25 and 26 and have links connected by pins 27a which engage the small grooves 25b, while rollers 28 engage the large grooves 25a in the sprockets. The chains 27 support steps 29 between them, and the rollers between the sprockets 25 and 26 are supported by inclined guide rails 30 which carry the chains through an upper run in which the steps 29 afford a flight of moving stairs, with the chains and steps returning in a lower run wherein they are supported and tensioned by conventional means between sprockets 25 and 26. As seen in FIG. 5 the steps 29 also have rollers 29a which are carried on guide rails 30a which parallel the rails 30.

Drive means for the escalator includes an electric motor 31 which is supported upon the frame 10 adjacent the lower shaft 23, a drive sprocket 32 on the motor shaft, an input sprocket 33 on the lower shaft 23, and a drive chain 34 which is trained around the sprockets 32 and 33.

The structure as described up to this point is essentially that of any transparent balustrade escalator, and provides only the setting for the present invention which will now be described.

A transverse handrail shaft 35 is best seen in FIGS. 4 and 5 to be mounted in the structural members 11 of the frame 10 on mounting brackets 36 in close proximity to the lower sprocket shaft 23, and journaled on the shaft 35 in the same vertical planes with the step chain sprockets 25 and 26 is a pair of handrail drive sprockets 37 which are identical with the sprockets 25 and thus include large roller engaging notches 37a and small pin engaging notches 37b which engage, respectively, the rollers 28 and the pins 27a of the step chains 27 as seen in FIG. 3. The step chains 27 are so supported by the lower step chain guide means as to engage with the sprockets 37 around a considerable arc at the lower portions of the sprockets as seen in FIGS. 2 and 3, so that the handrail sprockets are positively driven by the step chains.

As best seen in FIGS. 2, 4 and 5, the handrail drive sprockets 37 are provided with a plurality of hollow bosses 38 to which handrail sheaves 39 are secured by means of brackets 40 which are integral with the sheaves, and bolts and nuts 41. The sheaves 39 have their outer surfaces faced with rubber tires 42 to provide high frictional driving engagement with conventional endless rubber handrails 43 which are seen in FIGS. 1 and 2 to be guided around the bottoms of the sheaves 39, completely around the balustrades 17 on the guides 19, around upper guide roller means 44, through handrail tensioning means, indicated generally at 45, over intermediate guide roller means 46 and back to the sheaves 39. The term "sheave" is used herein in a nontechnical sense, since it is quite apparent that the element 39 is a wheel rather than a sheave; but because of its function in driving the endless belt-like handrail 43 it is thought that the term "sheave" is appropriate in the present disclosure.

As best seen in FIG. 2, in addition to the drive sprockets 37 and handrail sheaves 39 the handrail drive includes handrail supporting, guiding, and confining means including a first upper guide means in the form of a roller set 47a, a second upper guide means in the form of a roller set 47b, and lower guide means consisting of an articulated roller set 47c. Each of the upper roller sets 47a and 47b includes a yoke 48a or 48b, respectively, said yokes being respectively supported upon brackets 49a and 49b and carrying handrail guide rollers 50a and 50b, respectively, which support the handrails 43 and guide them into engagement with the sheaves 39 substantially at opposite ends of a horizontal diameter of the sheaves.

The lower handrail guide supporting and confining roller set 47c includes a series of bifurcated chain links 51 which are pivotally connected by pins 52 that serve as journals for rollers 53. One endmost chain link 51a is pivoted on a mounting arm 54 which in turn is carried by a pivot 55 on the frame; while the link 51b at the opposite end of the chain is provided with means 56 for adjustably and resiliently connecting it to a bracket 57 on the frame 10. It is seen that the handrail 43 is compressed against the rubber tire 42 of the sheave 39 by means of the rollers 53 through an arc of approximately 120.degree. around the bottom of the sheave.

Turning now to FIGS. 6 and 7, the handrail tensioning means 45 is seen to include an upright post 58 having upper and lower flanges 59 and 60 by means of which it is mounted on the frame 10. A carriage, indicated generally at 61, is slidably mounted upon the post 58 so that a tensioning sheave 62 which is journaled on the carriage may have its weight supported in the handrail 43 to tension the handrail between the upper roller guide 44 and the intermediate roller guide 46. The endless handrail 43, of course, tends to stretch somewhat as it is used, and in order to avoid the need for periodically adjusting the positioning of the tensioning sheave 62 the tensioning assembly 45 is made self-adjusting by the means which will now be described.

The carriage 61 consists of a sleeve 63 which makes an easy sliding fit on the post 58 and is provided with a band of holes below which a web 65 is welded to the sleeve and supports a cup, indicated generally at 66, which has a tapered side wall 67 surrounding the band of holes 64 in the sleeve. A set of balls 68 is mounted in the holes 64 and confined between post 58 and the tapered wall 67 of the cup; and a ball retaining snapring 69 fits into a groove in cup wall 67 above the balls. This arrangement permits the sleeve to slide freely downwardly on the post 58; but the sleeve is locked against upward movement because such movement causes the balls to be locked against the surface of the post by the tapered wall 67 of the cup.

A sheave journal block, indicated generally at 70, is provided with a stub shaft 71 upon which the tensioning sheave 62 is journalled, and a pair of arms 72 on the journal block 70 are apertured to receive bolts 73 which also impale holes in the web 65 and receive nuts 74. Compression springs 75 surround the bolts 73 and are confined between the web 65 and the arms 72 so that the journal block is adjustably and resiliently suspended from the web 65.

As is clear from the foregoing description, the structure of the carriage 61 permits the tensioning sheave 62 to move downwardly to compensate for stretch in the handrail 43; but the carriage locks against reversal as heretofore described.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom for some modifications will be obvious to those skilled in the art.

Claims

I claim:

1. In an escalator having a main frame with upper and lower end portions connected by an inclined portion, transverse sprocket shafts journalled in the upper and lower portions of the frame, a pair of spaced lower step sprockets on the lower shaft, a pair of spaced upper step sprockets on the upper shaft in the same vertical planes with the lower step sprockets, a pair of endless step roller chains trained about said sprockets, steps carried on said chains for movement through an upper run in which they afford a flight of moving stairs and a lower return run, means for driving one of said pairs of sprockets, a pair of balustrades in vertical planes flanking said upper run and having arcuate upper and lower end guides adjacent the sprocket shafts which are connected by an inclined guide for supporting a pair of moving handrails for said moving stairs, driven handrail means comprising, in combination: a transverse handrail shaft in the frame adjacent one of the sprocket shafts; a pair of handrail drive sprockets on the handrail shaft in the same vertical planes with the step sprockets, said drive sprockets being drivingly engaged by the step chains; a pair of handrail sheaves fixedly mounted on said drive sprockets in the same vertical planes as the balustrades; a pair of endless belt-like handrails trained beneath said sheaves and over said balustrades; a pair of handrail guide means mounted on the frame adjacent the sheaves, each of said guide means supporting one of the handrails and confining it to a path in which it firmly engages the sheave; and a pair of handrail tensioning means on the frame remote from the sheaves, each said tensioning means including an upright post, a sheave supporting carriage slidable on the post, a sheave jornalled on the carriage and having its weight carried in the handrail which passes beneath it, and means locking the carriage against upward movement on the post.

2. The driven handrail means of claim 1 in which the carriage includes a sleeve encircling the post and having a band of holes, a cup secured to the sleeve which has a downwardly converging wall surrounding the holes, and a set of balls projecting through said holes and bearing on the post and the cup wall so that upon upward movement of the sleeve the cup wall locks the balls against the post.

3. The driven handrail means of claim 2 which includes a horizontal web fixed on the sleeve at the bottom of the cup, and a sheave supporting journal resiliently suspended beneath the web.

4. The driven handrail means of claim 3 which includes a pair of upright bolts adjustably mounting the journal beneath the web, and compression springs surrounding the bolts between the web and the journal.

5. In an escalator having a main frame with upper and lower end portions connected by an inclined portion, transverse sprocket shafts journalled in the upper and lower portions of the frame, a pair of spaced lower step sprockets on the lower shaft, a pair of spaced upper step sprockets on the upper shaft in the same vertical planes with the lower step sprockets, a pair of endless step roller chains trained about said sprockets, steps carried on said chains for movement through an upper run in which they afford a flight of moving stairs and a lower return run, means for driving one of said pairs of sprockets, a pair of balustrades in vertical planes flanking said upper run and having arcuate upper and lower end guides adjacent the sprocket shafts which are connected by an inclined guide for supporting a pair of moving handrails for said moving stairs, driven handrail means comprising, in combination: a pair of handrail sheaves in the same vertical planes as the balustrades; means for driving said sheaves from the driving means; a pair of endless belt-like handrails trained in driving engagement with said sheaves and over said balustrades; and a pair of handrail tensioning means on the frame remote from the sheave, each said tensioning means including an upright post, a sheave supporting carriage slidable on the post, a sheave journalled on the carriage and having its weight carried in the handrail which passes beneath it, and means locking the carriage against upward movement on the post.

6. The driven handrail means of claim 5 in which the carriage includes a sleeve encircling the post and having a band of holes, a cup secured to the sleeve which has a downwardly converging wall surrounding the holes, and a set of balls projecting through said holes and bearing on the post and the cup wall so that upon upward movement of the sleeve the cup wall locks the balls against the post.

7. The driven handrail means of claim 6 which includes a horizontal web fixed on the sleeve at the bottom of the cup, and a sheave supporting journal resiliently suspended beneath the web.

8. The driven handrail means of claim 7 which includes a pair of upright bolts adjustably mounting the journal beneath the web, and compression springs surrounding the bolts between the web and the journal.

9. The driven handrail means of claim 5 which includes roller guide means supporting the handrail adjacent both sides of the handrail tensioning means.