IE911890A1 - A production process for shoes - Google Patents

Abstract

A process for production of shoes is illustrated. A lasted margin (3) is roughened by grinding and portion (2) of the edge of a lasted upper (1) is roughened using a machine (10) having serrated discs (13) mounted loosely on rotating support rods (14). The inside margin of a sole is roughened using a vertical grinding insert (24) mounted above a drive wheel (21) for guiding the inside margin of the sole against the grinding insert (24). Bonding of the upper to the sole is achieved by initially applying a primer coat of adhesive and allowing this to dry. Subsequently, an adhesive\hardener mixture is applied and allowed to dry. When bonding is to take place, both the primer and the adhesive\hardener mixture are re-activated by heating. The upper and sole are pressed together using inflatable cushions to create an even pressure.

Description

The invention relates to a development of the invention described in our co-pending Irish Patent Application no. 2645/88.

More particularly, the invention relates to a development of 5 this invention for production of shoes having a lower weight but which have substantially the same strength, comfort, flexibility and waterproofing qualities as those produced by the process of the above-mentioned invention.

According to the invention there is provided a process for 10 producing shoes comprising the steps of :preparing an upper by carrying out the sub-steps of : lasting an upper over an insole; roughening the surface of the lasted margin by 15 grinding; blowing the upper and insole clear of particles; - 3 applying a primer coat of diluted adhesive to the roughened lasted margin; applying a coat of adhesive/hardener mixture to the primed and roughened lasted margin; and drying out solvents in the primer adhesive and in the adhesive/hardener mixture by prolonged heating; preparing a sole by carrying out the sub-steps of :roughening the inside margin of a blank sole by 10 grinding; blowing the sole clear of particles; applying a primer coat of diluted adhesive to the roughened margin; applying a coat of adhesive/hardener mixture to 15 the primed and roughened margin; and allowing the adhesives to dry; - 4 sealing the sole to the upper by carrying out the sub-steps of:re-activating the adhesives by heating the sole and the rubber to a temperature in the range of 180° C to 200° C; positioning the upper on the sole; and pressing the upper against the sole by inflating surrounding air cushions.

In one embodiment, the sole margin is roughened by gripping 10 the sole between a driven lower drive wheel mounted about a horizontal axis, and an upper grinding insert mounted about a vertical axis and having a lower horizontal grinding surface.

Preferably, the grinding wheel has a peripheral side grinding surface for simultaneously grinding the inside surface of a sole wall.

Ideally, the steps of preparing the upper include the step of roughening portion of the edge wall of the lasted upper.

In this latter embodiment, preferably, the step of roughening portion of the edge wall of the lasted upper comprises placing - 5 the edge wall portion against rotating serrated discs mounted loosely on a support.

The invention will be more clearly understood from the following description of some preferred embodiments thereof, given by way of example only with reference to the accompanying drawings in which :Fig 1 is a side view of a grinding operation for uppers forming part of a process of the invention; Fig 2 is a diagrammatic plan view of this operation; Fig 3 is a perspective view from the underneath of a lasted upper at this stage of the process; Fig 4 is a perspective view of a grinding operation for a sole; and Fig 5 is a cross-sectional view in the direction of the 15 arrows V-V of Fig 4.

A process of the invention for preparing a shoe is carried out by preparing an upper, preparing a sole, and subsequently bonding the upper to the sole. - 6 Preparation of the upper is carried out by cutting leather into various pieces according to a desired pattern and stitching together the pieces to form an upper. The pieces of leather and sub-assemblies of the leather are colour coded with colour markings on the edges for identification of the size and style for the particular piece or sub-assembly. The upper is then placed over a last and is steam treated to soften the leather and prepare it for lasting.

The lasting operation is carried out by pressing the upper 10 around the bottom of the last against the underside of an insole. While the upper is being pressed, glue is injected between the lasted margin of the upper and the insole. In this embodiment, the lasting operation is carried out in two stages, the front of the upper being lasted firstly and mid and heel portions being lasted afterwards.

To ensure that the upper retains the shape of the last and to set it into position, the lasted upper is heat-set at a temperature in the range 150°C - 160°C for several minutes. At this stage, the upper is firmly bonded to the insole and is set in shape.

The next step in the process involves roughening the lasted margin to assist bonding of the margin to a sole. This step is carried out by running the lasted margin against a grinding wheel. This may be carried out either manually or automatically.

Where the shoe is to have a sole with either a side wall or a projection protruding upwardly along the side of the shoe to 5 a greater or lesser extent, portion of the edge of the lasted upper is roughened. This operation is illustrated in Figs 1 to 3 in which a lasted upper 1, an edge 2 and a lasted margin are shown. A roughening machine indicated generally by the reference numeral 1 is used for this operation. The machine comprises a back plate 11 driven by a motor, not shown.

The back plate 11 supports a central spindle 12 which rotates with the back plate 11. Serrated discs 13 are supported on support rods 14. The support rods 14 are mounted at one end to the back plate 11 and at the other to a front dish-shaped guide plate 15. Each support rod 14 carries approximately twenty serrated discs 13. The apertures of the discs 13 are substantially larger than the diameter of the support rod 14 so that they are loosely mounted. Finally, the machine 10 comprises a tapered guide wall 16 which in operation is fixed in position surrounding all of the serrated discs except those which are to impinge against the upper edge 2 in use. The guide wall 16 is movable in an axial direction for adjustment prior to operation of the machine to set the extent to which the edge of the lasted upper is to be roughened. - 8 In use, the back plate 11 is driven and thus, the fixed assembly including the central spindle 12, the support rods 14 and the guide plate 15 all rotate together. The serrated discs 16 which are loosely mounted on the support rods are urged outwardly by the centrifugal force. The lasted upper 1 is placed against the machine with the lasted margin 3 impinging against the guide wall 16, the edge to be roughened impinging against the serrated discs 16 and the lasted upper 1 above the portion to be roughened being held against the guide plate 15. Thus, the portion between the guide wall 16 and the guide plate 15 is roughened by rotation of the serrated discs 13. Because the serrated discs 13 are loosely mounted, they do not tear the leather but merely roughen it under the centrifugal force, which is relatively small. The lasted upper 1 is moved around in the direction of the arrow B until all of the edge portion 2 has been roughened.

After the roughening operations, compressed air is used to blow the lasted upper 1 clear of particles and subsequently a filling material is applied to the outside of the insole within the lasted margin 3.

For adhesion of the upper, a primer coat of diluted adhesive is applied to the roughened portions of the lasted upper. When this has been allowed dry, a coat of adhesive/hardener mixture is applied over the primer. The lasted upper is then placed in a heating cabinet for a prolonged period in order to - 9 dry out the solvents of the primer and of the adhesive/hardener mixture.

The process for preparation of soles is now described. Initially, the inside margin of a rubber sole corresponding to the lasted margin is roughened by grinding. This operation is carried out using a machine 20 illustrated in Fig 4 and 5. In this drawing, for clarity, parts which are relatively easily understood by those skilled in the art are not illustrated. The machine 20 comprises a drive wheel 21 driven by a belt for rotation about a horizontal axis in the direction of the arrow C. Mounted above the wheel 21 there is a vertical rotating spindle 23 at the end of which there is fixed a cylindrical grinding insert 24 having both peripheral and end grinding surfaces. A sole 25 is placed with the bottom surface engaging the wheel 21 and the grinding insert 24 engaging the inside margin, which may or may not include the inside surface of a side wall. The sole is moved on the rotating grinding insert 24 until all of the inside margin has been roughened. Rotation of the drive wheel 21 assists in this operation. It will be appreciated that if the sole has a side wall, the inside of is roughened by the peripheral grinding surface of the grinding insert 24. After the grinding operation, compressed air is used to blow the sole clear of particles. Subsequently, a saltreat primer is applied to the roughened margin and is allowed dry. When the saltreat primer has - 10 dried, an adhesive/hardener mixture is applied over the primer and allowed to dry.

When both the upper and sole has been prepared, the upper is positioned carefully on the sole so that it fits neatly. The upper and sole are then placed together in a heater which heats them to a temperature in the range of 180° - 200° to reactivate the adhesives. When the adhesives have been reactivated, the upper and sole are together placed in a pressing machine having lower and side inflatable cushions.

The cushions are inflated to urge the upper against the sole. Because the cushions are inflated, they take up the exact form of the sole and upper so that even pressure is applied throughout. Further, because inflatable cushions are used, the pressing machine is suitable for all sizes and shapes of shoes.

Finally, if required the sole is additionally stitched to the upper.

It will be appreciated that because of the manner in which both the sole and the upper are roughened and each have two coats of adhesive applied and the manner in which they are applied, a very strong bond is created between the upper and the sole. Further, because of the use of air pressure to press the upper and sole together, even pressure is applied and there are no weak points in the bonding of the sole to the - 11 upper. It will further be appreciated that the manner in which the sole and upper are roughened is both effective and efficient and results in very few discards in use. This is important for efficiency of the process.

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

Claims (2)

1. A process for producing shoes comprising the steps of:preparing an upper by carrying out the sub-steps of : 5 lasting an upper over an insole; roughening the surface of the lasted margin by grinding; blowing the upper and insole clear of particles; 10 applying a primer coat of diluted adhesive to the roughened lasted margin; applying a coat of adhesive/hardener mixture to the orimed and roughened lasted margin; and drying out solvents in the primer adhesive and 15 in the adhesive/hardener mixture by prolonged heating; preparing a sole by carrying out the sub-steps of:IE 911890 - 13 roughening the inside margin of a blank sole by grinding; blowing the sole clear of particles; applying a primer coat of diluted adhesive to 5 the roughened margin; applying a coat of adhesive/hardener mixture to the primed and roughened margin; and allowing the adhesives to dry; sealing the sole to the upper by carrying out the 10 sub-steps of :re-activating the adhesives by heating the sole and the rubber to a temperature in the range of 180° C to 200° C; positioning the upper on the sole; and 15 pressing the upper against the sole by inflating surrounding air cushions.

2. A process as claimed as in claim 1, wherein the sole margin is roughened by gripping the sole between a lower - 14 drive wheel mounted about a horizontal axis, and an upper grinding insert mounted about a vertical axis and having a lower horizontal grinding surface. A process as claimed in claim 2, wherein the grinding wheel has a peripheral side grinding surface for simultaneously grinding the inside surface of a sole wall. 15 6 A process as claimed in any preceding claim, wherein the steps of preparing the upper include the step of roughening portion of the edge wall of the lasted upper. A process as claimed as in claim 4, wherein the step of roughening portion of the edge wall of the lasted upper comprises placing the edge wall portion against rotating serrated discs mounted loosely on a support. A process substantially as hereinbefore described with reference and as illustrated in the accompanying drawings . A shoe whenever prepared by a process as claimed in any preceding claim.