Handrails For Escalators And Travolators

Abstract

A handrail for an escalator or travolator and comprising a strip of generally C-shaped cross section. A lengthwise succession of transverse slots through the arms of the C-shaped cross section facilitate bending of the strip about its transverse axis.

Description

The invention relates to handrails for escalators or travolators and to a method of making such handrails.

With the coming of long escalators and passenger conveyors the higher loads imposed on handrails have necessitated more and more complex and costly drive systems. One of the major drawbacks of such systems has been lack of synchronization between the handrail and the escalator or passenger conveyor bed and a tendency for uneven slipping in the drive system with consequent jerking of the handrail. In addition the friction drives have necessitated high-static tensions being applied to the handrails with consequent stretch and deformation of the handrails.

The invention provides an escalator or travolator handrail comprising a strip of semirigid material of generally C-shaped cross section in which there is a succession along the length of the strip of transverse slots which extend through the arms of the C-shaped section whereby the handrail may bend about its transverse axis.

One or more flexible reinforcing elements may extend longitudinally within the unslotted portion of the handrail, which elements are formed from a material the tensile strength of which is high in relation to that of said semirigid material.

Preferably the slots which extend through the opposed arms of the handrail are aligned with each other.

It is preferred that there is a succession of teeth upstanding from the inside surface of the base of the strip, which teeth are capable of engagement by a positive drive for the handrail.

It is further preferred that the gaps between the teeth are aligned with the slots aforesaid.

The invention includes a handrail of the type described above in combination with a flexible resilient outer cover which extends around the outside of the C-shape and has means to engage the tongues provided by the remaining portion of the arms of the C-shape after the slots have been cut.

Preferably the engaging means are pockets in the outer cover.

The invention further provides a method of producing an escalator or travolator handrail which comprises the steps of continuously extruding a bar of semirigid material of C-shaped cross section, and forming a plurality of transverse slots through the arms of the C-shape.

Preferably the slot-forming step is effected by an apparatus which is arranged to move with the handrail, as the handrail moves away from the point of extrusion.

It is preferred that the C-shaped extrusion is formed with a continuous projection from the base on the same side of the base as the arms, and that slots are formed in the projection at the same time as slots are formed in the arms to divide the projection into teeth.

Some specific embodiments of the invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is a sectional view of an escalator handrail;

FIGS. 2a and 2b are respectively a plan view and side elevational view of the handrail;

FIG. 3 is a view showing a cover for the handrail;

FIG. 4 is a sectional view showing the handrail as fitted to an escalator and

FIG. 5 is a diagrammatic view showing one end of an escalator.

As shown in FIG. 1 the cross section of the handrail is substantially C-shaped so that the handrail can slide on a T-section guide rail such as that shown in FIG. 4. The strength and rigidity of the lips of the handrail are important to prevent the handrail from being pulled off the guide rail accidentally or deliberately. On the other hand the lips and the whole handrail structure must be sufficiently flexible to go round the newel wheels and driving pulleys on the escalator as shown in FIG. 5. This means that a compromise between lip strength and handrail flexibility has previously been necessary.

The embodiment of the invention described below reduces the drawbacks set out above by provision of teeth for a positive driving system and by separation of the functions of the components of the handrail enabling high lip strength to be achieved with the required longitudinal flexibility.

Referring to FIG. 1 the handrail comprises tensile reinforcing members 1 which may be of cord or of wire having a high tensile modulus, such as glass fiber cord, or steel cord, or wire or may be a steel or woven fiber tape. It will be appreciated that any suitable number of reinforcing members may be employed. The reinforcing members are embedded in a suitable thermoplastic material 2 which is of the section shown. Slots 3 are cut or molded at regular intervals in the lips of the thermoplastic structure as shown in FIG. 2. In addition integral teeth 4 are formed at regular intervals along the center of the section. A cover, such as shown in FIG. 3, comprising a material 5 of suitable elastomeric nature such as natural or synthetic rubber with fabric edge strips 6 is attached to the reinforced thermoplastic structure substantially by the engagement of slotted lips 7 of the thermoplastic structure in holes 8 of the cover. The cover may be bonded to the thermoplastic structure by means of a suitable adhesive or other means.

The thermoplastic used may be any synthetic resin of suitable strength such as polyethylene, polypropylene, nylon, polyvinylchloride etc. When a cord reinforcement is used it may have transverse short fibers or barbs spun into it to increase the mechanical bond with the thermoplastic resin.

In use the handrail operates as follows. On the superstructure, where passengers may hold on to it, the handrail is guided on a rail 9 shaped substantially as shown in FIG. 4 so that the loads imposed by passengers on the sliding surfaces of the handrail and the guide rail are reacted on the thermoplastic surfaces of the handrail or on the fabric lips of the handrail cover. The guide rail may itself be of a thermoplastic material or may be metallic. Power to drive the handrail is transmitted either to a newel wheel 10 or to an intermediate wheel on the underside of the escalator or passenger conveyor as indicated in FIG. 5. The newel wheels and driving wheel (if fitted) have teeth 12 which engage with the teeth 4 of the handrail. In this way the handrail is prevented from slipping relative to the driving wheel.

When the handrail is bent round a newel wheel or elsewhere the neutral axis of bending is at the center of the tensile reinforcing members 1 and the slotted lips of the handrail move together or apart, depending on the direction of curvature. Thus the only major resistance to bending is that provided by the relatively thin thermoplastic section encompassing the tensile reinforcement and strains are minimized except in the elastomeric cover which is well able to accommodate them.

The thermoplastic section is formed by a conventional extrusion process whereby the tensile reinforcing members are fed into a crosshead die and covered by the thermoplastic material. The extruded composite passes through conventional air or water cooling systems and is carried on a conventional haul-off system to the cutting system.

Within the cutting system the slots 3 are cut by any suitable cutting method such as shearing, milling or grinding in which a single cutter or a plurality of cutters are arranged to move at the speed of the extrudate whilst cutting the transverse slots. On completion of the transverse cutting cycle the cutter or cutters are accurately moved toward the extruder to be in position to cut the next slot or series of slots.

When the slotted extrudate leaves the cutting system it is sufficiently flexible, by virtue of the slots, to be coiled on a suitable drum. An endless handrail can then be made by taking a suitable length of the extrudate and joining the ends of the tensile reinforcing members so that the slot pitch length is maintained over the joint. The joint can then be placed into a suitable mold into which further thermoplastic material is injected to fill the space around the reinforcing members at the joint and to form the base, lugs and teeth at the joint. Finally the cover 5 is fitted on the entire endless handrail as shown in FIG. 3 and a suitable joint is made in the cover either by welding, if a thermoplastic elastomer is used, or by vulcanizing if the elastomer is thermosetting.

The handrail when made as described herein has two main advantages. The first is that the handrail lips are relatively stiff and therefore the handrail will not come off its guide rails, and the second is that the drive into the handrail is positive because of the teeth and a simple driving system can be used with low static tension in the handrail. Also synchronization between the handrail and the escalator or conveyor bed is ensured.

Claims

I claim:

1. A handrail comprising a core of semirigid material of generally C-shaped cross section and having along its length a succession of transverse slots formed through the arms of the C-shape in combination with an outer cover of flexible resilient material which extends around the outside of the core and has means to engage the tongues provided by the remaining portions of the arms of the C-shape section after the slots have been cut.

2. A handrail as claimed in claim 1 wherein one or more flexible reinforcing elements extend longitudinally within the unslotted portion of the handrail, which elements are formed from a material the tensile strength of which is high in relation to that of said semirigid material.

3. A handrail as claimed in claim 1 wherein the slots which extend through the opposed arms of the handrail are aligned with each other.

4. A handrail as claimed in claim 1 wherein there is a succession of teeth upstanding from the inside surface of the base of the strip, which teeth are capable of engagement by a positive drive for the handrail.

5. A handrail as claimed in claim 4 wherein the gaps between the teeth are aligned with the slots aforesaid.

6. A handrail as claimed in claim 1 wherein the engaging means are pockets in the outer cover.