US3490324A

US3490324A - Safety device for a guillotine

Info

Publication number: US3490324A
Application number: US660171A
Authority: US
Inventors: Gerald W Dahle
Original assignee: WILHELM DAHLE METALLWARENFABRIK Firma
Current assignee: WILHELM DAHLE METALLWARENFABRIK Firma
Priority date: 1967-08-07
Filing date: 1967-08-07
Publication date: 1970-01-20
Anticipated expiration: 1987-01-20

Description

55% 1970 G. w. DAHLE SAFETY DEVICE FOR A GUILLOTINE Filed Aug. 7, 1967 GERALD w. DAHLE iNVENTUR:

United States Patent M 3,490,324 SAFETY DEVICE FOR A GUILLOTINE Gerald W. Dahle, Coburg, Germany, assignor to Firma Wilhelm Dahle Metallwarenfabrik, Coburg, Germany Filed Aug. 7, 1967, Ser. No. 660,171 Int. Cl. B26d 7/22 US. Cl. 83-397 Claims ABSTRACT OF THE DISCLOSURE A shield-type safety device made of flexible material for a guillotine having progressively cutting, shear-type, relatively movable blades. The shield is pivotally mounted on the movable blade and has a helically shaped edge which extends into the space between the blades. As the blades close in cutting action the shield is progressively withdrawn as its edge bares against a clamp member on the work support.

The invention relates to a safety device for a guillotine having relatively movable blades operable in a shear-like manner, and more particularly guillotines for cutting of paper. The safety device may also be used on shears used for cutting cardboard, sheetmetal and the like.

Safety devices of the above-mentioned type are required to an increasing extent for preventing accidents on guillotines, in order to prevent the hands of an operator from passing between the knives, so that the operator suffers considerable injury. A known safety device of this kind, used on paper cutting apparatus, consists of a plate which is loosely hinged to the cutting knife and one of the lateral edges of which projects downwardly beyond the cutting knife so that before the cutting knife and the counter-knife meet it impinges on the hand of an operator, thus giving him warning so that the operator is still able to draw away his hand. This device is, in the true sense, merely a warning device, since it is not able effectively to prevent the inflicting of injury unless, as the warning plate impinges on the hand of the operator, the cutting process is immediately stopped.

It has furthermore already been proposed to design a safety device for a paper cutting guillotine in which when the hand is laid on the cutting apparatus within range of.

the knife the relative movability of the knives in the cutting direction is blocked. This blocking device requires, however, an extremely robust and costly mode of construction, since in order to block the cutting movement considerable rotary or impact moments must be absorbed.

According to one aspect of the invention there is provided a safety device for a guillotine having relatively movable blades operable in a shear-like manner, the safety device comprising a shield at least part of which in the open position of the blades of a guillotine, is adapted to extend into the space between the blades to protect at least one of the blades and means, which during shearing movement of the guillotine, is adapted progressively to remove the shield from its space between the blades.

According to another aspect of the invention there is provided a safety device for a guillotine having relatively movable blades operable in a shear-like manner, the safety device comprising a shield which in the open position of the blades of a guillotine, has an edge portion which is adapted to extend obliquely with respect to the cutting edge of one of the blades and transversely thereof so that at least a portion of the shield extends into the space between the blades to protect at least one of the blades and during shearing movement of the guillotine is adapted progressively to move from the space between the blades. Due to the design of the safety device one of the two knives is always covered in the open position. As

3,490,324 Patented Jan. 20, 1970 the blades draw near to each other the shield is progressively withdrawn from the intermediate space between the blades, so as not to hinder the cutting step. This withdrawal of the shield takes place gradually so that at no time is there room for the fingers of an operator to pass into the intermediate space immediately between the two knives. Thus necessarily the shield must engage the fingers before the knife can reach and cut the fingers. In this way it constitutes an effective covering for the cutting blade, so that injury is avoided in an extremely effective manner, since in conventional paper cutting guillotines the counter-blade is, as a rule, not sharp. Thus, no injury will be caused by any pressure which, if it comes to the worst, may be exerted by the cutting blade, over the shield, on a hand placed between the shield and the counter-blade. It is especially advantageous if the shield is made of a flexible material, so that when it impinges on an obstacle it yields and bears directly on the cutting edge of the knife to be protected by it. t

In order to ensure that the withdrawal movement of the shield out of the intermediate space between the two blades of a conventional paper cutting guillotine takes place independently in dependency on the position of the blade, an oblique lateral edge of the shield preferably has the shape of a helix which, as the blades close, rolls on a face arranged laterally of the counter-blade, the shield meanwhile rotating. With this form of the invention, the shield is rotatably mounted on the cutting blade. The pivoting axis extends parallel to the longitudinal line of the cutting blade. The covering casing is acted-upon by a restoring force which is effective about its pivot-axis, in the direction towards the intermediate space between the blade and the counterblade, so that it always endeavours to spring back resiliently into its covering position or to bring its helical lateral edge to bear on the rolling counter-face.

An illustrative embodiment of the invention will now be described with reference to the accompanying drawings, in which:

FIGURE 1 is a perspective view of a paper cutting apparatus with the upper knife in the open position;

FIGURE 2 is a section taken along the line IIII of FIGURE 1, with the knives open;

FIGURE 3 is a sectional illustration corresponding to FIGURE 2, with the knives completely closed after the termination of the cutting step; and

FIGURE 4 is an exploded view of the cutting knife design in the cutting apparatus according to FIGURE 1.

The manually-actuated paper cutting apparatus consists of a cutting table 1, serving as a support for the paper to be cut, a cutting knife or blade 2 carried by a lever arm 3 pivotally mounted on the cutting table 1, a counter-knife or blade 4 which is rigidly secured on the lateral edge 5 of the cutting table 1. The lever arm 3 has a handle 6 which facilitates movement of the cutting" knife 2 to and away from the counter-knife 4. In operation, the cutting step takes place, when during its downward movement the knife 2 travels past the counter-knife 4. Spaced from the cutting table 1, and arranged before the lateral edge 5 is a device or bar 7 which clampingly engages paper to be cut between itself and the table 1.

Secured for pivotal movement about an axis 9-10 of the lever 3 is a shield in the form of covering casing 8 in the shape of a tubular shell segment which completely covers over the cutting knife 2 in the open position. The covering casing 8 is made from a flexible plastics material and is secured in the region of its

narrow sides

11, 12 to circular-segment-shaped curved bowed

members

13, 14. The bowed

members

13, 14 are formed at their free ends with bores 15, 16 which, with the aid of bolts or screws 17 are secured to the lever arm and constitute a pivotal bearing for the covering casing 8. One of the two pivotal bearings of the covering casing 8 is provided with a compression spring 18 which acts on the bowed member 14 and urges it anti-clockwise (as shown in the drawings), in the direction towards the intermediate space between the

knives

2 and 4.

The cover 8 has a lateral helical edge 19 which is located so that it is disposed in the region between the

knives

2 and 4. The axis of the helix of the edge 19 is preferably coincident with the axis 9-10. The axis 9-10 also preferably constitutes the axis of curvature of the curved bowed

members

13 and 14.

Due to the action of the spring 18- at least part of the lateral edge 19 of covering casing 8 is pressed against the device 7 in every position of the lever 3 to thereby apply pressure to the device 7 so that a sheet of paper to be cut is clamped between the device 7 and the table 1.

In operation, if the cutting knife 2 is in the open position (FIGS. 1 and 2), the covering casing 8 bears on the surface of the device 7 at a point near to the bowed member 14. Due to the oblique, helical line of the lateral edge 19, the exposed length of the cutting knife 2 is completely covered, from below, by the covering casing 8, so that contact of the cutting knife 2 is not possible. If, then, the cutting knife 2 is moved downwardly in the cutting direction, then the side 19 of the covering casing 8 rolls on the surface of the pressing device 7 with the result that it is pivoted about the axis 9-10, in the direction of arrow 20, against the restoring force provided by the spring 18. In this way, in exact correspondence with the increasing cut and the increasing overlapping of the cutting edges of the two

knives

2, 4, the intermediate space between the

knives

2, 4 is always just closed. The covering casing 8 is therefore withdrawn out of the intermediate space between the

knives

2, 4 proportionally as the

knives

2 and 4 close.

If the operator unintentionally puts his hand into the intermediate space between the two

knives

2 and 4, his hand will always be between the device 7 and the cover 8. If, in this condition, the cutting knife 2 is displaced downwardly, then the operators hand will be jammed between the covering casing 8 and the device 7, without however the cutting knife contacting the hand. In this way, injury is effectively avoided. Due to the resilient pivoting mounting of the covering casing 8 and the slight- 1y resilient form thereof, the most that can happen is that the cutting knife 2 will cut into the material of the covering casing which, for this purpose, is made from a softer material than the cutting knife 2, so as to prevent blunting of the knife. When an object passes between the device 7 and the casing 8, if the cutting step is continued, further movement of the covering casing on the surface of the device 7 is prevented, since this is no longer possible due to the relationship of forces which becomes effective.

What I claim is:

1. A safety device for a guillotine having relatively movable blades cutting by an increasing overlapping of their cutting edges, the safety device comprising a shield at least part of which, in the open position of the blades, is adapted to extend into the space between the blades to protect at least one of the blades and means, which, with increasing overlapping of the cutting edges, proportionally withdraws the shield from the space between the blades.

2. A safety device for a guillotine having relatively movable blades cutting by an increasing overlapping of their cutting edges, the safety device comprising a shield which, in the open position of the blades, has an edge portion which is adapted to extend obliquely with respect to the cutting edge of one of the blades and transversely thereof so that at least a portion of the shield extends into the space between the blades to protect at least one of the blades and during cutting movement of the guillotine is adapted progressively to move from the space between the blades.

3. A safety device as claimed in claim 1 in which said means includes an edge portion of the shield which, in the open position of the blades of the guillotine, is adapted to extend obliquely to the cutting edge of one of the blades and transversely thereof so that at least a portion of the shield extends into the space between the blades.

4. A safety device as claimed in claim 3, in which the edge portion is helical in shape.

5. A safety device as claimed in claim 4 in which the shield is adapted to be rotatably mounted on one of the blades of the guillotine so that during cutting movement of the blades the edge portion engages a stationary member to cause relative rotation between the shield and the blade on which it is rotatably mounted.

6. A safety device as claimed in claim 5 in which the axis of rotation of the shield is parallel to the cutting surface of the blade on which it is adapted to be mounted.

7. A safety device as claimed in claim 5 in which the shield is adapted to rotate relative to the blade on which it is rotatably mounted against the action of resilient means.

8. A safety device as claimed in claim 5 in which the shield is secured between two arcuate members which are adapted to be rotatably connected to one of the blades of the guillotine.

9. A safety device as claimed in claim 8 in which the axis of rotation of the shield is coincident with the axis of curvature of the arcuate members.

10. A safety device as claimed in claim 5 in which the axis of rotation of the shield is coincident with the axis of the helix.

11. A safety device as claimed in claim 3 adapted to be used with a guillotine having a pressure device for holding down material being cut, part of the said edge portion of the shield being adapted to engage the pressure device on the guillotine during cutting movement of the blades.

12. A safety device as claimed in claim 1 in which the shield is arcuate in cross-section.

13. A safety device as claimed in claim 1 in which the shield is made from a material which is softer than the material of the blades of a guillotine to which it is to be attached.

14. A safety device as claimed in claim 12 in which the shield is made from a flexible plastics material.

15. A safety device as claimed in claim 2, in which the edge portion is helical in shape.

References Cited UNITED STATES PATENTS 1,576,949 3/1926 Carbonaro 83397 2,190,049 2/ 1940 Sperry 83-397 X 2,270,473 1/1942 Porcelli 83397 X 2,518,076 8/1950 Scherig 83397 2,763,324- 9/1956 Loverch et al. 83397 X 3,063,320 11/1962 Beagley 83-397 WILLIAM S. LAWSON, Primary Examiner US. Cl. X.R. 83-453, 544, 607