IE79094B1 - Manufacture of bricks - Google Patents

Abstract

Irregular bricks are produced by cutting (12) regular bricks by sliding a feed table containing a brick at a correct alignment against a guide into a rotary cutter having cutting tips which are uniform in a circumferential direction. There is a continuous stream of water coolant down the cutter. After cutting, the cut bricks are dried. Cut bricks are joined at their cut faces by a liquid epoxide resin applied at a thickness of 1 - 3mm. Dust from the cut bricks is applied to the resin to provide a uniform consistency and colour in the uniform brick. There is initial curing in an interim stack (80) on firm insulating boards. Final curing (19) takes place in a final curing stack (90) with each layer of bricks being laid on a sheet of mechanically insulating and undulating material to provide insulation and air access to all faces.

Description

Manufacture of Bricks The invention relates to a method for manufacturing bricks, more particularly irregular bricks such as plinth bricks, angle and cant bricks, bullnose bricks or any type of irregular brick.

At present, production of such bricks is as an extremely time-consuming process as individual moulds must be made up for each type of brick. In practice, because of the wide range of different types of irregular brick, there needs to be a large number of moulds and this can be very expensive and further, production organisation is difficult. This leads to relatively long lead times in the marketplace and also to a high brick cost.

Further, in kiln firing of bricks, the setting procedure can cause a variation of colour from the standard brick type.

The invention is directed towards providing a method for manufacturing bricks of this type whereby the production costs are lower and the lead time is shorter than has heretofore been the case. Another object is to provide a method whereby an improved level of colour consistency is achieved.

According to the invention, there is provided a method of manufacturing irregular bricks, the method comprising the steps of:25 cutting standard bricks by mounting each brick on a feed table at a desired cutting angle, and moving the feed table to cause the brick to be cut by a rotary cutter having circumferentially uniform cutting tips - 2 and being continuously cooled and lubricated by a water stream down the cutter; applying a liquid epoxide resin to cut faces of the cut bricks, at a thickness of 1 to 3mm; mixing brick dust from the cutting operation to the resin at edges of the cut faces; joining cut bricks at their cut faces to provide irregular bricks; storing the irregular bricks on an interim curing stack on firm platforms for six to twelve hours at 20°C to 24°C for initial curing; and transferring the irregular bricks to a final curing stack laid in layers, each on a resilient and undulating insulation layer, and leaving them stand for 2 to 4 days at 20°C for final curing.

Preferably, the standard bricks are mounted on the feed table abutting against an adjustable guide, and the base of the table has a high-friction surface.

In one embodiment, the cutter has a thickness of 2 - 3mm, a tip length of 25 to 35mm, and a gap between tips of 7 9mm.

In a further embodiment, the cutter speed of rotation is 2800 to 3200 rpm.

Preferably the adhesive is prepared by mixing a liquid epoxide resin base with an epoxide activator.

In one embodiment, the base comprises bisphenol-aepichlorohydrin resin with average molecular weight greater than 650. The activator may comprise nonyl phenol.

In a further embodiment, the irregular bricks are wrapped in-situ in the final curing platform by a water-sealing film.

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only with reference to the accompanying drawings in which:Fig. 1 is a flow chart illustrating a manufacturing method of the invention; Fig. 2 is a perspective from above showing a cutting operation of the method; Fig. 3(a) is a diagrammatic side view showing preparation of a brick for cutting, and Fig. 3(b) is a diagrammatic side view showing the brick being cut; Fig. 4 is a close-up detailed side view showing part of a cutter; Fig. 5 is a close-up detailed front view in the direction of the arrow A in Fig. 4 showing a cutting tip in more detail; Fig. 6 is a diagrammatic perspective view showing the cutting operation; Fig. 7 is a front view of a stack of cut bricks being dried, and Fig. 8 is a plan view of this stack; Fig. 9 is a diagrammatic representation of the adhesive mixing and application operations to form irregular bricks; Figs. 10 and 11 are front and plan views respectively of an interim curing stack of irregular bricks; Figs. 12 and 13 are plan and front views respectively showing a final curing stack of irregular bricks; and Fig. 14 is a front view showing a stack of finished irregular bricks ready for transport.

Referring to the drawings, the manufacturing method of the invention is illustrated in overview form in Fig. 1 in which the method is indicated by the numeral 1 and the individual steps by the numerals 10 to 20 inclusive. The first steps of the method are carried out at a cutting station 30 shown in Figs. 2 to 6. At the station 30, regular bricks 31 are cut to provide cut bricks 60 which are mounted on drying pallets 32. The cutting station 30 comprises a fixed frame 33 having a feed table support 34 on which is mounted a movable feed table 35 mounted on wheels 36 running on rails 37. A brick guide 38 is mounted on the feed table 35. A cutter assembly 39 is mounted over the feed table 35 and comprises a rotary cutter 40 and a coolant duct 41 for providing a stream 42 of coolant on the cutter 40 during the cutting operation. The cutter 40 comprises a steel base plate 43 to which are secured diamond cutter tips 44. The cutter tips 44 have a length in the circumferential direction of 25 - 35mm and in this embodiment are 30mm long and there is a gap of 7 8mm between them. The cutter tips 44 have a uniform thickness along their length and in this embodiment the thickness is 2.5mm and more generally should be in the range of 2 - 3mm.

As shown most clearly in Fig. 6, the guide 38 comprises an 5 adjustment wheel 50 and a clamp 51 for setting the desired angle for a guide plate 52 to which the regular brick 31 is abutted during the cutting operation. The surface of the feed table 35 is of a rubber material which provides a high friction for support of the regular brick 31 during cutting.

As indicated by the step 10 in Fig. 1, the guide 38 is aligned by rotation and clamping of the adjustment wheel 50 to provide the correct angle for the guide plate 52. In step 11 a regular brick 31 is placed at the guide 38 abutting against the guide plate 52. In step 12 the feed table 35 slides against the cutter assembly 39 when it is in the lower position. The cutter speed is 3000 rpm and more generally 2800 to 3200 rpm. As shown most clearly in Fig. 6, the cutter cuts a regular brick 31 while rotating in the direction of the arrow B. Because there is a continuous stream of coolant water 42 and because of the construction of the cutter 40 (shown most clearly in Figs. 4 and 5) it has been found that there is a very flat uniform cut face on the regular brick 31. Uniformity of the cut face is extremely important in the invention. A further advantageous which arises from the construction of the cutter is that there is a relatively long life for the cutting tips 44.

In step 13 the cut bricks are stacked in a drying area as shown in Figs. 7 and 8. The cut bricks are indicated by the numeral 60 and the cut faces by 61. The cut bricks 6 0 are mounted on a pallet 62 and are placed in a hot air stream provided by a fan heater 63 at a temperature of 18 - 22°C. The cut bricks 60 are dried in this manner for a time period in the range of twenty four to thirty six hours. It has been found that this is sufficient to dry the bricks to the required level. It is envisaged, however, that the bricks need not be dried if a wet bonding resin is used in subsequent steps.

Referring to Fig. 9, as indicated by step 14 an activator and a base for an adhesive are mixed. A container 70 contains an activator which is an epoxide hardener containing nonyl phenol. A container 71 contains liquid epoxide resin comprising bisphenol-A-epichlorohydrin resin having an average molecular weight of greater than 650. The base and hardener are mixed in the ratio of two parts base to one part hardener on a board 7 3 to provide an adhesive mix 74. At this stage, brick dust 72 from the cutting operation is added to provide a colour and consistency which is uniform with the brick. This step is indicated by the step 15 in Fig. 1 and in step 16 two cut bricks 60 are joined together after the adhesive mix 74 has been applied to a thickness in the range of 1 -3mm, and preferably 2mm. The joined bricks then form an irregular brick 75. An additional step to improve the cosmetic appearance of the irregular brick 75 is to apply brick dust to exposed resin at the joined edges in step 17. This further helps to provide a uniform appearance throughout the irregular brick 75.

In step 18 the irregular bricks 75 are stored in an interim curing stack 80 in layers placed on polystyrene boards 81. The polystyrene boards are firm in construction and thus provide a sound base for the irregular bricks 75, while at the same time providing a degree of resilience to prevent weight of the stack on the lower layers from dislodging bricks. The interim curing stack 80 is built up gradually so that when the second layer is added the irregular bricks 75 in the first layer have cured to a state sufficient to take the weight of the second layer without any distortion. This begins the curing process at a temperature of 20 - 24°C.

After a time period in the range of six to twelve hours, the irregular bricks 75 are transferred to a final curing stack 90 which comprises a pallet 91 over which is laid an air-bubble plastics sheet 91. This sheet provides a resilient and undulating surface to provide mechanical insulation for the irregular bricks 75, while at the same time allowing air to access all of the surfaces. Again, the final curing stack 90 is built up gradually by transfer from the interim curing stacks 80. The final curing stack is left in place in a hot air stream for a time period in the range of two to four days at a temperature of 22 - 24°C for final curing.

The interim and final curing steps are indicated by the steps 18 and 19 and finally, in step 20 the stack 90 is shrink-wrapped by film 101 to provide a water seal around the stack 100. This is an extremely simple way of storing the irregular bricks 75 for transport without the need for additional handling. The irregular bricks 75 are then ready for transport.

It has been found that the invention provides for production of irregular bricks 75 in an extremely simple manner by use of relatively inexpensive items of equipment and little labour input. This production process is significantly less expensive than moulding the bricks individually and the end product has been found to be more consistent in colour.

The invention is not limited to the embodiments hereinbefore described, but may be varied in construction and detail.

Claims (10)

1. A method of manufacturing irregular bricks, the method comprising the steps of:cutting standard bricks by mounting each brick on a feed table at a desired cutting angle, and moving the feed table to cause the brick to be cut by a rotary cutter having circumferentially uniform cutting tips and being continuously cooled and lubricated by a water stream down the cutter; applying a liquid epoxide resin to cut faces of the cut bricks, at a thickness of 1 to 3mm; mixing brick dust from the cutting operation to the resin at edges of the cut faces; joining cut bricks at their cut faces to provide irregular bricks; storing the irregular bricks on an interim curing stack on firm platforms for six to twelve hours at 20°C to 24°C for initial curing; and transferring the irregular bricks to a final curing stack laid in layers, each on a resilient and undulating insulation layer, and leaving them stand for

2. To 4 days at 20°C for final curing. A manufacturing method as claimed in claim 1, wherein the standard bricks are mounted on the feed table abutting against an adjustable guide, and the base of the table has a high-friction surface.

3. A manufacturing method as claimed in claim 1 or 2,

4. A manufacturing method as claimed in claims 1 to 3, wherein the cutter speed of rotation is 2800 to 10 3200 rpm.

5. . A manufacturing method as claimed in any preceding claim, wherein the adhesive is prepared by mixing a liquid epoxide resin base with an epoxide activator. 15 5 wherein the cutter has a thickness of 2 - 3mm, a tip length of 25 to 35mm, and a gap between tips of 7 - 9mm.

6. A manufacturing method as claimed in claim 5, wherein the base comprises bisphenol-aepichlorohydrin resin with average molecular weight greater than 650.

7. A manufacturing method as claimed in claim 5 or 6 , 20 wherein the activator comprises nonyl phenol.

8. A manufacturing method as claimed in any preceding claim, wherein the irregular bricks are wrapped in-situ in the final curing platform by a watersealing film. 25

9. A manufacturing method as described with reference to and as illustrated in the accompanying drawings .

10. i Bricks whenever produced by a method as claimed in any preceding claim.