GB1572638A - Sliding door track mechanism - Google Patents

Description

(54) IMPROVED SLIDING DOOR TRACK MECHANISM (71) We CECIL JAMES WATKINS and SIMON ROBERT WATKINS of 309 Kingsway, Hove, Sussex, BN3 4LT, Both British Citizens, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to sliding door arrangements, and is particularly, though not exclusively, concerned with such arrangements for refrigerated areas.

According to the present invention there is provided a sliding door arrangement for closure of an opening formed in a wall, comprising a substantially horizontally extending supporting rail of elongate transverse crosssection mounted above the opening, the lateral faces of the rail being at an acute angle to the upward direction in the plane of the opening, a door member hung from the rail for movement longitudinally thereof by means of two carriage blocks each of which is movably seated on the rail by a main wheel which, when the door is in an at least partially open position, runs on the upper edge of the rail and further wheels which engage the upper lateral face of the rail, the rail having recesses in its upper edge into which, when the door is moved to its closed position, the main wheels engage so that the door moves downwardly, and by virtue of said angled lateral face, inwardly toward the wall.

The term "sliding" is used as it is conventional: the carriage blocks do, of course, roll on the rail. The carriage block may also include further wheels which engage the outer lateral surface of the rail.

Preferably the lower edge of the door is provided with sealing means which, in use, is compressed by said downward movement and the lateral and upper edges of that face of the door which is turned toward the wall are provided with sealing means which, in use, is compressed against the wall by said inward movement.

In a preferred arrangement each carriage block comprises a body portion with an elongate slot therein in which the main wheel is rotatably mounted, a first set of said further wheels rotatably mounted on the block at 900 to the main wheel and arranged to bear on the upper lateral face of the supporting rail and a second set of said further wheels rotatably mounted on the block at 900 to the main wheel and arranged to bear on the lower lateral face of the supporting rail, the second set of further wheels being positioned further from the main wheel than the first.

Preferably the leading carriage block in the direction of closure has an auxiliary wheel positioned so as to engage the upper edge of an auxiliary rail mounted alongside the supporting rail in the region of the recess provided for reception of the trailing carriage block, whereby the leading carriage block can pass freely over this recess.

The arrangement may also include drive means for the door having a motor arranged to.

drive an endless elongate flexible driving member to which the carriage blocks are connected: in order to reduce the starting load, the preferred arrangement provides that each carriage block includes a bell-crank lever pivotally mounted therein with a first arm to which the endless driving member is secured and a second, shorter, arm arranged so that, with the door in its closed position, upon application by the member to the first arm of the lever of a force in the direction of opening, the second arm is urged downwardly against the support rail to lift the carriage block.

One embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an elevation of a sliding door in stallation; Figure 2 is a cross-section on line II-II of figure 1; and Figure 3 is a cross-section on line III-III of figure 2.

Figure 1 shows a sliding door arrangement for a door-way 1 in the wall 2 of a refrigerated area. A door 3 (shown in its closed position) is supported on a horizontally extending rail 4 which is secured to the wall by brackets 5. The door is suspended from the rail by two carriage blocks 6, 7 which are able to slide along the rail, and a pair of floor-mounted retaining blocks 8 are provided for the bottom of the door. As can be seen from figure 2, the rail 4 is mounted at an angle of 45" to the vertical.

The leading carriage block 7 is shown in figures 2 and 3 and has a body 10 which is formed as a monolithic casting. The body has a central elongate slot 11 in which a main steel wheel 12 and a similar auxiliary wheel 13 are rotatably mounted by ball races on a pin 14 positioned centrally of the block. The wheel 12 bears squarely on the upper edge of the rail 4.

The body has 45" flats 15, 16 on which are respectively mounted a first set of three wheels 17 and a second set of two wheels 18. These further wheels 17, 18 are rotatably mounted, again by ball races and pins, with their axes at 90" to that of the wheel 12. The wheels 17 bear on the upper inclined face of the rail 4, and the wheels 18 on the lower inclined face at a position further from the main wheel than the wheels 17, so that the carriage block is firmly located on the rail but can move freely in the longitudinal direction. In each case the outer ball-race may constitute the wheel itself. The trailing carriage block 8 is identical to the carriage block 7 except that the wheel 13 is omitted and replaced by a spacer sleeve.

The carriage blocks are secured to the door by adjustable units 20 (figure 2). Each unit 20 comprises a pair of cast brackets 21, 22 bolted to the block and door respectively and connected together by a bolt 23 which may be screwed into and out of the bracket 22 to effect height adjustment. The bracket 21 has offset mounting lu,gs so that it can be reversed to suit doors of 4' or 6" thickness.

In the upper edge of the rail 4 are formed a pair of recesses 24 (see figure 3) so positioned that when the door is moved to its closed position, the wheels 12 of the carriage blocks 7, 8 drop into the recesses. The recesses each have a 45" lead-in 25. Due to the angle of the rail 4, the carriage blocks and door move simultaneously both downwardly and inwardly towards the wall 2.

The side of the door facing the wall is provided, along three edges, with sealing members, and as a result of the inward movement the door is tightly urged against the wall, thus compressing the sealing members and providing a good seal. The bottom edge of the door is also provided with a sealing member. Conversely, when the door is moved from its closed position, the wheels 12 of the carriage blocks are raised up out of the recesses back on to the top edge of the rail 4, so that the door is once again free, away from the wall and floor, and can travel smoothly along the track to its fully open position.

In this embodiment the open position of the door (shown dotted in figure 1) is such that both carriage blocks occupy a position to the left of the left-hand (first) rail recess (as viewed in the drawing). It is necessary to prevent the leading carriage block 7 from falling into this recess during opening and closing of the door.

Accordingly, an auxiliary rail 40 (figure 2) is secured to the lower face of the rail 4 in the region of the first recess. As the carriage block 7 passes, the wheel 13 thereof bears on the auxiliary rail 40 and these two components thus take over the role of the wheel 12 and rail 4 and ensure unimpeded passage of the carriage block over the first recess. When the door reaches the closed position, the wheels 12 of the leading and trailing carriage blocks fall into their respective recesses, since in the former case the auxiliary rail is absent whilst in the latter there is no auxiliary wheel 13. The secondary rail 40 may extend not only over the extent of the first recess but over substantially the whole length of the rail 4 (with the exception, of course, of the second recess). As the wheels 18 run beneath the auxiliary rail, this prevents the carriage blocks lifting of the rail.

As can be seen from figure 1, movement of the door is effected by means of an electric motor 31, reduction gear 32, drive sprocket 33, a roller chain 34, and idler sprocket 35. The chain is fastened to the carriage blocks 7, 8.

Although the recesses in the rail have a tapered lead-in for smooth movement of the door, nevertheless a considerable force is required for initial opening movement of the door since this involves lifting the door to clear the recesses, and also to free it from the wall and floor. In order to reduce the starting torque required from the motor, therefore, the chain 34 is not secured directly to the carriage blocks 7, 8 but is in each case secured to one arm 41 of a bell-crank lever 42 which is pivoted in the block on the pin 14 and whose other (shorter) arm 43 carries a small roller 44. Thus initial movement of the chain causes the lever 42 to pivot clockwise (as viewed in figure 3): the roller 44 engages the upper edge of the rail 4 and, as the lever pivots, lifts the carriage block 7, thus facilitating the movement of the wheel 12 up the 45" slope 30a of the recess 30. The ratio of the lever arms 41, 43 may typically be 21A 1 whereby a substantial mechanical advantage is obtained for starting. An adjustable stop screw 45 is provided to limit rotation of the lever 42 and is adjusted so that the roller 44 is just clear of the top of the rail 4 when the wheel 12 has been lifted out of the recess.It will be observed that the body 10 of the carriage block is symmetrical and has provision for an adjuster screw 45': thus the same design of carriage block can be used for doors opening in the opposite direction, simply by reversing the bellcrank lever 42.

A further feature of the door arrangement is that the motor is provided with an electromagnetic clutch which is energised only when the motor is actually operating, so that when the motor is not energised it does not place any drag on the chain drive. This, together with a lever-operated manual door opening arrangement which enables the initial opening load to be overcome and the door raised up the slope of the recess to ride upon the guide rail edge once again, is a useful safety feature since it permits the door to be opened manually in case of power failure and reduces the danger of persons becoming trapped within the refrigerator.

The electrical control system for the door arrangement is generally conventional, apart from the provision of the electromagnetic clutch which is connected (via a transmormer to suit the clutch voltage) in parallel with the motor. Limit switches 60, 61 (figure 1) are provided in the usual way.

WHAT WE CLAIM IS: 1. A sliding door arrangement for closure of an opening formed in a wall, comprising a substantially horizontally extending supporting rail of elongate transverse cross-section mounted above the opening, the lateral faces of the rail being at an acute angle to the upward direction in the plane of the opening, a door member hung from the rail for movement longitudinally thereof by means of two carriage blocks each of which is movably seated on the rail by a main wheel which, when the door is in an at least partially open position, runs on the upper edge of the rail and further wheels which engage the upper lateral face of the rail, the rail having recesses in its upper edge into which, when the dool is moved to its closed position, the main wheels engage so that the door moves downwardly, and, by virtue of said angled lateral face, inwardly toward the wall.

2. A sliding door arrangement according to claim 1 in which the lower edge of the door is provided with sealing means which, in use, is compressed by said downward movement and the lateral and upper edges of that face of the door which is turned toward the wall are provided with sealing means which, in use, is compressed against the wall by said inward movement.

3. A sliding door arrangement according to claim 1 or 2 in which the carriage block includes further wheels which engage the outer lateral surface of the rail.

4. A sliding door arrangement according to claim 3, each carriage block cdmprising a body portion with an elongate slot therein in which the main wheel is rotatably mounted, a first set of said further wheels rotatably mounted on the block at 900 to the main wheel and arranged to bear on the upper lateral face of the supporting rail and a second set of said further wheels rotatably mounted on the block at 900 to the main wheel and arranged to bear on the lower lateral face of the supporting rail, the second set of further wheels being positioned further from the main wheel than the first.

5. A sliding door arrangement according to any one of claims 1 to 4 in which the leading carriage block in the direction of closure has an auxiliary wheel positioned so as to engage the upper edge of an auxiliary rail mounted along-side the supporting rail in the region of the recess provided for reception of the trailing carriage block, whereby the leading carriage block can pass freely over this recess.

6. A sliding door arrangement according to any one of the preceding claims in which the recesses in the rail are each provided with a tapered lead-in.

7. A sliding door arrangement according to any one of the preceding claims further comprising drive means for the door having a motor arranged to drive an endless elongate flexible driving member to which the carriage blocks are connected.

8. A sliding door arrangement according to claim 7 in which each carriage block includes a bell-crank lever pivotally mounted therein with a first arm to which the endless driving member is secured and a second, shorter, arm arranged so that with the door in its closed position upon application by the member to the first arm of the lever of a force in the direction of opening, the second arm is urged downwardly against the support rail to lift the carriage block.

9. A sliding door arrangement according to claim 7 or 8 in which the motor is arranged to drive the endless driving member via an electromagnetic clutch so connected as to be engaged only when the motor is operated.

10. A sliding door arrangement substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. the opposite direction, simply by reversing the bellcrank lever 42. A further feature of the door arrangement is that the motor is provided with an electromagnetic clutch which is energised only when the motor is actually operating, so that when the motor is not energised it does not place any drag on the chain drive. This, together with a lever-operated manual door opening arrangement which enables the initial opening load to be overcome and the door raised up the slope of the recess to ride upon the guide rail edge once again, is a useful safety feature since it permits the door to be opened manually in case of power failure and reduces the danger of persons becoming trapped within the refrigerator. The electrical control system for the door arrangement is generally conventional, apart from the provision of the electromagnetic clutch which is connected (via a transmormer to suit the clutch voltage) in parallel with the motor. Limit switches 60, 61 (figure 1) are provided in the usual way. WHAT WE CLAIM IS:

1. A sliding door arrangement for closure of an opening formed in a wall, comprising a substantially horizontally extending supporting rail of elongate transverse cross-section mounted above the opening, the lateral faces of the rail being at an acute angle to the upward direction in the plane of the opening, a door member hung from the rail for movement longitudinally thereof by means of two carriage blocks each of which is movably seated on the rail by a main wheel which, when the door is in an at least partially open position, runs on the upper edge of the rail and further wheels which engage the upper lateral face of the rail, the rail having recesses in its upper edge into which, when the dool is moved to its closed position, the main wheels engage so that the door moves downwardly, and, by virtue of said angled lateral face, inwardly toward the wall.

2. A sliding door arrangement according to claim 1 in which the lower edge of the door is provided with sealing means which, in use, is compressed by said downward movement and the lateral and upper edges of that face of the door which is turned toward the wall are provided with sealing means which, in use, is compressed against the wall by said inward movement.

3. A sliding door arrangement according to claim 1 or 2 in which the carriage block includes further wheels which engage the outer lateral surface of the rail.

4. A sliding door arrangement according to claim 3, each carriage block cdmprising a body portion with an elongate slot therein in which the main wheel is rotatably mounted, a first set of said further wheels rotatably mounted on the block at 900 to the main wheel and arranged to bear on the upper lateral face of the supporting rail and a second set of said further wheels rotatably mounted on the block at 900 to the main wheel and arranged to bear on the lower lateral face of the supporting rail, the second set of further wheels being positioned further from the main wheel than the first.

5. A sliding door arrangement according to any one of claims 1 to 4 in which the leading carriage block in the direction of closure has an auxiliary wheel positioned so as to engage the upper edge of an auxiliary rail mounted along-side the supporting rail in the region of the recess provided for reception of the trailing carriage block, whereby the leading carriage block can pass freely over this recess.

6. A sliding door arrangement according to any one of the preceding claims in which the recesses in the rail are each provided with a tapered lead-in.

7. A sliding door arrangement according to any one of the preceding claims further comprising drive means for the door having a motor arranged to drive an endless elongate flexible driving member to which the carriage blocks are connected.

8. A sliding door arrangement according to claim 7 in which each carriage block includes a bell-crank lever pivotally mounted therein with a first arm to which the endless driving member is secured and a second, shorter, arm arranged so that with the door in its closed position upon application by the member to the first arm of the lever of a force in the direction of opening, the second arm is urged downwardly against the support rail to lift the carriage block.

9. A sliding door arrangement according to claim 7 or 8 in which the motor is arranged to drive the endless driving member via an electromagnetic clutch so connected as to be engaged only when the motor is operated.

10. A sliding door arrangement substantially as herein described with reference to the accompanying drawings.