GB2147377A

GB2147377A - Castor for a hand trolley

Info

Publication number: GB2147377A
Application number: GB08423542A
Authority: GB
Inventors: Herbert Sachser
Original assignee: Schulte Soehne Co A GmbH
Current assignee: Schulte Soehne Co A GmbH
Priority date: 1983-09-29
Filing date: 1984-09-18
Publication date: 1985-05-09
Also published as: GB2147377B; DE3335272A1; ES281642U; ES281642Y; GB8423542D0; FR2552716A1

Abstract

The runner wheel (12) of a castor has spaced apart flanges (22) to engage between ribs (21) of a conveyor belt (20). An externally toothed annular brake body (23) of smaller outside diameter than the diameter of the flanges (22) surrounds wheel cylinder (19) between the flanges (22). When the castor is standing on a flat floor, the brake body (23) hangs freely on the wheel cylinder (19) between the flanges. When the flanges (22) engage between the ribs (21) of the belt (20), the annular brake body is pressed upwardly by the ribs (21) against the runner wheel cylinder (19) and a downwardly facing holding member formed as a locking tongue (27) and provided on a wheel fork head (26) engages between teeth (24) the brake body (23) to prevent rotation of the brake body (23) and thus rotation of the wheel. Locking tongue (27) extends downwardly from annular casing portion (28) of fork head (26) and has a reinforcement (30). <IMAGE>

Description

SPECIFICATION Castor for a hand trolley The invention relates to castors for hand trolleys, particularly shopping trolleys, for use on inclined grooved conveyor belts, the castors being so constructed that when the trolley is wheeled onto a grooved conveyor belt it is automatically braked.

In one previously proposed castor of this kind (German utility model number 82 11 565), the runner wheel comprises two independently rotatable wheel discs which are each provided with a peripheral wheel flange, between which is a runner wheel cylinder. An annular brake body disposed around the runner wheekl cylinder is of an inside diameter that is substantially larger than the outside diameter of the runner wheel cylinder so that when the wheel is on a flat floor, the brake body hangs loosely on the runner wheel cylinder and at its lower portion has a relatively large clearance between its inside periphery and the outside peripheral surface of the runner wheel cylinder. The brake body is of such a dimension that its outside peripheral surface is at a small spacing from the plane of the floor or even slightly touches same.When the castor runs onto a conveyor belt which is provided with longitudinal ribs and which in particular extends at an inclined angle, the flanges engage between the ribs and the ribs urge the annular brake body upwardly so that the castor is supported solely by way of the brake body which has its external surface pressed against a brake block member which is fixed to the back of the wheel fork. Since the brake body is also in frictional contact with the underside of the runner wheel cylinder, the castor is immobilised on the conveyor belt by frictional engagement.Although that design provides that the castor is securely fixed in position on a conveyor belt provided with longitudinal ribs, the wheel fork however has to be designed to mount the brake block member, in which respect in particular the back of the wheel fork requires a bridge portion which increases the length of the bearing cup or collar.

According to the invention, there is provided a trolley castor comprising a runner wheel mounted on an axle in a wheel fork and having spaced apart wheel flanges to engage grooves of a conveyor belt and an externally toothed annular brake body which is disposed between the flanges, is of smaller outside diameter than the outside diameter of the flanges and, when the flanges stand on a floor, hangs freely on a runner wheel cylinder disposed between the flanges with its outer periphery extending downwardly approximately as far as the floor, wherein a head of the wheel fork mounts a downwardly facing holding member in the form of a locking tongue to engage the teeth of the brake body when the wheel flanges engage in grooves of a conveyor belt and ribs of the conveyor belt press the brake body upwardly into engagement with the underside of the runner wheel cylinder.

Such a configuration in respect of the holding member means that on the one hand the production of a brake block member is completely eliminated while on the other hand there is no need for the back of the fork to be extended beyond the region of a runner rim.

A holding member which is particularly simple to produce is provided if, as is proposed in accordance with an advantageous embodiment, the locking tongue is formed at the peripheral region of the annular casing above the wheel fork axle in the form of a tang or lug on the wall thereof, that projects from the lower edge thereof.

In order on the one hand to be able to fix the externally toothed brake body without play and on the other hand to enhance the stability of the locking tongue, the locking tongue preferably has a reinforcement that increases the thickness thereof, at its region of engagement. The reinforcement of the locking tongue is preferably formed by a bead extending in a vertical direction.

The invention is diagrammatically illustrated by way of example with reference to the accompanying drawings in which: Figure 1 shows a partly broken-away side view of a castor for a transport trolley according to the invention, standing on an inclined conveyor belt, with brake elements which are form-lockingly in engagement: Figure 2 shows a view of the castor of Fig.

1, in vertical cross-section through the runner wheel axle taken on line ll-ll of Fig. 1; and Figure 3 shows a view in horizontal section taken on line Ill-Ill of Fig. 2 of a locking tongue that forms a component of a wheel fork of the castor.

The castor essentially comprises a wheel fork 10 which, besides the pivotal arrangement illustrated, can also be in the form of a pedestal or support castor, and a runner wheel 12 mounted on an axle 11. In the case of the runner wheel shown in the drawing, the axle which is formed as a bolt is embraced by an axle sleeve 14 which is gripped between limb portions 1 3 of the wheel fork 10. Fixedly connected raceway rings 1 5 of ball bearings 1 6 are engaged with the sleeve 14 at both ends thereof.Two wheel discs which are joined together to form a wheel rim 17, for example by riveting, are supported non-displaceably in the axial direction on the ball bearings 1 6. At its outside periphery, the wheel rim 1 7 carries two tyre portions 18, each of which is of an angular cross-section, and the tyre portions 1 8 are disposed and mounted on the rim 1 7 in such a way that the horizontal limb portions together form a runner wheel cylinder 1 9 while the vertical limb portions form external wheel flanges 22 which are disposed at a spacing ccrresponding to a multiple of the pitch spacing of the ribs 21 of a conveyor belt 20.Disposed between the flanges 22 is an annular brake body 23 which surrounds the runner wheel cylinder 1 9 with relatively large clearance therefrom. In the embodiment iliustrnted, the brake body 23 is provided on its outside periphery with teeth 23 which are recessed into a middle portion of the width thereof, annular beads 25 provided one on each side of the teeth 24 projecting slightly outwardly therebeyond. The outside diameter of the annular brake body 23 corresponds to the outside diameter of the flanges, less the clearance between the outside diameter of the runner wheel cylinder 1 9 and the inside diameter ot the brake body 23.

In that respect, the clearance is less than the height of the ribs 21 and may be, for example, approximately haif the height of the ribs. Disposed on a ,wheel fork block portion 26 which connects the limb portions 1 3 of the wheel fork 19, is a downwardly facing holding member in the form of a locking tongue 27 which, when the brake body 23 rests on the ribs 21 of the conveyor belt 20, engages into the gaps between the teeth 24.

The locking tongue 27 extends downwardly from an annular casing portion 28 of the metal fork head 26 and projects downwardly beyond the lower edge of the annular casing 28. The locking tongue 27 has a reinforcement 30 which 3 capable of filling the gaps in the teeth and which is formed for example as a bead that extends in a vertical direction.

As can be seen in particular from Fig. 1, the illustrated embodiment is a steerable castor which accordingly, has a ball race cup 31, embraces the drawn-in fork head 26, with the interposition of a row of balls, and which is centrally connected to a over cup 32 which engages over the top of the fork head and which is also supported on the fork head in known manner by way of a row of balls.

In the illustrated embar'i'Tent of castor, the ball bearings 1 6 and possibly the wheel rim 1 7 are clad in an axial direction outwardly by cover discs 33 which are gr!pped between the sleeve 14 and the respective limb portion 1 3 of the wheel fork 10, by way of the axle 11.

That arrangement on the one hand avoids fouling of the bearing means and on the other hand provides a visually attractive appearance for the castor. As long as the castor is disposed on a flat floor and the flanges 22 stand on the floor, the annular brake body 23 is supported loosely at the upper apex of the cylinder 19, and the runner wheel can rotate unimpededly about its axle 11. If however the castor runs onto a conveyor belt 20 which is provided with ribs 21, the flanges 22 penetrate into the gaps between the ribs 21 and cause the ribs 21 to come into contact with the outside peripheral surface of the annular brake body 23 so that the brake body 23 is urged upwardly into the position shown in the drawings. When that occurs, the locking tongue 27 engages into a gap between the teeth 24 on the brake body 23 and prevents the castor wheel rotating.

Claims

1. A trolley castor comprising a runner wheel mounted on an axle in a wheel fork and having spaced apart wheel flanges to engage grooves of a conveyor belt and an externally toothed annular brake body which is disposed between the flanges, is of smaller outside diameter than the outside diameter of the flanges and, when the flanges stand on a floor, hangs freely on a runner wheel cylinder disposed between the flanges with its outer periphery extending downwardly approximately as far as the floor, wherein a head of the wheel fork mounts a downwardly facing holding member in the form of a locking tongue to engage the teeth of the brake body when the wheel flanges engage in grooves of a conveyor belt and ribs of the conveyor belt press the brake body upwardly into engagement with the underside of the runner wheel cylinder.

2. A trolley castor according to claim 1, in which the locking tongue is formed at the peripheral region of an annular casing above the axle of the wheel fork, as a lug on the wall thereof, and projects downwardly from the lower edge thereof.

3. A trolley castor according to claim 1 or claim 2, in which at its region of engagement with the teeth of the brake body the locking tongue has a reinforcement which increases the thickness thereof.

4. A trolley castor according to claim 3, in which the reinforcement of the locking tongue is formed by a bead extending in a vertical direction.

5. A trolley castor substantially as hereinbefore described and illustrated with reference to the accompanying drawings.