US2839103A - Safety guards for rotary blade fabric cutters - Google Patents

Description

June 17, 1 J. E. PRINCE ETA].

SAFETY GUARDS FOR ROTARY BLADE FABRIC CUTTERS Filed Nov. 4, 1955 E m E z MEN m TB I n SAFETY GUARDS FoR ROTARY BLADE FABRIC CU'I'IERS Joseph Edward Prince and Stanley Haynes, Wrexham,

Wales, assignors to British Celanese Limited, a corporation of Great Britain Application November 4, 1955, Serial No. 545,099

Claims priority, application Great Britain November 16, 1954 2 Claims. (Cl. 143-159 This invention relates to safety guards, and particularly to safety guards for cutter blades which are adapted to be driven continuously in a cutting plane through a cutting zone.

According to the present invention'a safety guard for a cutter blade of the kind referred to comprises a pivoted plate-like guard element adapted to be mounted and to swing substantially parallel to the cutting plane and loaded so as to swing into the cutting zone, but movable against its loading out of said zone. If, as is usually the case, the operative has access to the blade from both sides of the cutting plane, it is clearly desirable to provide two such guard elements, pivoted about a common axis and disposed one on each side of the cutter blade. The safety guard of the present invention serves, whenever or insofar as the blade in the cutting zone is not guarded by the presence of the material to be cut, to prevent the operative from moving his hand into contact with the cutter blade, or at least to give him due warning, by contact, that he is about to do so.

The invention is particularly applicable to portable rctary-knife garment-cutting machines adapted to cut simultaneously a'number of layers of fabric constituting considerable thickness, and will be described hereinafter in relation to such machines. In such machines the knife is mounted for rotation on a horizontal spindle above a mobile horizontal base which is adapted to be guided about a cutting-out table on which superimposed layers of fabric rest. Since the cutting plane is vertical, the guard elements can be pivoted on a horizontal axis above and in front of the cutting zone and can be loaded by gravity, by being pivoted about a point forward of their centres of area or by being weighted at their rear ends. When the machine is moved in towards the edge of the fabric, to engage and cut the fabric, the guard elements are swung upwards clear of the cutting zone by the engagement of the fabric itself beneath the elements, assisted if desired by the operatives hand acting on the front ends of the elements. The elements then rest, dur ing cutting, with their trailing ends pressing on the surface of the fabric, but lightly enough to give the operative some freedom to manipulate the fabric from outside the cutting zone. The trailing ends of guard elements may be provided with lightly constructed small wheels which rotate when the machine is cutting, to avoid disturbing the layers of fabric. By pivoting the elements inde pendently, when the line of cut runs close to the edge of the fabric layers, the element passing clear of the edge immediately drops while the other remains supported on the fabric surface.

It is desirable that the height of the pivot of the guard elements should be adjustable in accordance with the thickness of material to be cut, so that the lower edge of the elements, when swung into a horizontal position, can be just clear of the upper surface of the material or can rest thereon in a nearly horizontal position. With the guard correctly adjusted in this way, entry of the operatives hand into the cutting zone while the blade is in engagement with the fabric can be absolutely prevented since the guard elements cannot be tipped either forward or backward to give accidental access to the blade. However, it is an important advantage of the invention that it still aifords a considerable measure of protection to the operative, even when the pivot of the guard elements is not correctly adjusted but is above the optimum. It is desirable that the pivot point of the guard elements should be spaced well above the lower edge thereof; this I facilitates the swinging back of the guard by engagement with the fabric. I h The material of which the guard elements are made preferably such that the operative can see the cutting zone through the elements. For this purpose the ole;- ments are preferably made of stout transparent plastic sheet material. Even in this case the transparency of the material can be obscured by lint, dust, or the like, and it is preferred to form therein perforations or windows to give a clearer view of the cutting point, though these should not be made large enough to give access to the cutting zone. Alternatively, the plate-like elements may be made of wire mesh or coarse wire gauze material. The guard elements may be shaped to suit the circumstances of their employment. Thus they may be provided, in front of the pivot, with a notch for engagement by the operatives hand to facilitate tipping up of the guard when the material to be cut is first engaged. The rear edge of the elements may be suitably shaped to clear the parts of the machine which they might otherwise foul or to come into properly timed engagement with suitable stops to prevent their being accidentally tipped too far forward. The lower edge of the guard elements should be profiled so that the front end thereof slopes upwards from the upper surface of the material and does not tend to dig into it and disturb the lie of the layers of fabric.

By way of example, one form of rotary cutting machine provided with a safety guard in accordance with the invention will now be described in greater detail with reference to the accompanying drawing, which is a side elevation of the machine.

The machine comprises a shallow rectangular base plate 1 mounted over small wheels 2 or rollers and bevelled at its edges so as to pass easily beneath the layers of fabric to be cut. Rising from the centre of the plate is a standard 3 which carries, fitting closely to it, a 5 in. diameter circular cutting knife 4 rotatable about a horizontal axis. The front aspect of the standard 3 is narrow, so that it, and the knife 4, can pass easily through a cut made by the knife. The lowest part of the edge of the knife 4 passes into a groove 6 in the base plate 1, entering through a throat 7 that is carefully shaped and adjusted to prevent the bottom layer of fabric being drawn in by the knife. Above the knife 4, the standard 3 carries an electric motor 8 for driving the knife, and behind the motor extends a horizontal handle 9 with motor switches 10 in convenient proximity thereto.

To the front of the motor 8 is fixed the safety guard of the present invention. This comprises a bracket 14 which extends first horizontally forward and then vertically downwards, and to the vertical part of this bracket there is secured, by means of a thumb-screw 15, a vertically slotted plate 16 whose height can be adjusted and fixed by means of the thumb-screw 15. At the lower edge of the slotted plate 16 is a horizontal spindle 17 about 1 /4 in. long, on the ends of which are freely pivoted two sheets 18, 19 of transparent cellulose acetate material of /3 in. gauge. The sheets are about 2 /2 in. in depth and about 7 in. in horizontal length, of which 4 in. lies behind the spindle 17 and 2% in. in

front. Below and to the rear of the pivot are a series of vertical slots 22 about %in. in width giving a clear view, when the sheets are, in the horizontal position, of w the front edge 23 of the knife 4. Thelrear edge of the knife is completely enclosed in a rear guard 24, and needs no further protection. The upper edge 25 of the sheets 18, 19 is appropriately shaped to clear such parts of the machine as they might encounter but with portions 26 adapted to engage parts of the machine so as toprevent the front ends of the sheets from being tilted downward s too far. The front ends of the sheets are shaped with a notch 27 for engagement by the operatives hand to I facilitate tilting of the sheets into a horizontal position.

Thelo'wer edges 28 of the sheets are formed, at their front ends, with a downward step 29-, which lies over the edge of the base-plate 1,whei'e the fabric level is lower than it is over the base plate, as shown by dotted line 30 which indicates the height of the layers of fabric which could pass under the guards when they are adjusted as shown on the drawing.

Having described our invention what We desire to secure by Letters Patent is: g a

l. A transportable rotary-knife fabric cutting machine of the type having'a circular knife mounted for rotation 1 a q iz n al spind e laq e a while b s p t s 7 machine comprising at least one plate-like guard pivoted about an axis parallel to and in front of theknife spindle and extending both to the front and to the rear of said axis, said guard being freely" swingable to and from a position in which its rear end covers an otherwise exposed portion 'ot'edge; of the knife between said axis and the base plate and being loaded to swing into said position, and-being swin'gable out of said position by pressure o lf jts Ifiontend, remotepfrom saidiedge, I

2. A machine according to claim 1, comprising means for vertically adjusting the guard axis with reference to the base plate.

Wilson Feb. '16, 1954

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