Chain link with a plate featuring a pincer, for haul-off of a sheet material

Abstract: A chain link of the type in which a plate (11) is provided with a pincer (12) for hauling-off a sheet material comprises a bracket (14) extending laterally in an overhung fashion from the said plate (11) and forming in its upper portion a fixed jaw (13) which cooperates with a movable jaw (15) which is pivoted to the said plate and extends through an aperture in the said bracket; a spring (21) is arranged between the said fixed and mobile jaws to thrust the movable jaw supportively against the fixed jaw in order to lock the said sheet material between the jaws.

Description: The present invention relates to a chain link, one plate of which featuring a pincer, which is economical to manufacture and use and which is intended for the purpose of hauling-off sheet material, particularly but not solely a plastic film. As is known to persons with ordinary skill in the art, downstream of a plastic film extruder provision must be made for means that will haul-off the extruded film to a subsequent work-station, at the same time keeping the film appropriately taut. For such purpose it is known to use chain type haul-off devices disposed laterally to the extruded film and featuring means adapted to grip the said film and haul it off in a forward direction. The said haul-off means have to be constructed so that they permit, initially, the laying of the film on the chain and, subsequently, the positive engagement of the said film for its haul-off. For example, DE-A-3 109 237 discloses a clasping device comprising an elastic element bended in the shape of a pincer. The open movement of the pincer is not determined, since deformations of the elastic element depends on the direction of the pushing action. DE-A-3 001 742 discloses a pincer with an upper element pivoted so as to have a predetermined open movement. A sliding element is inserted in the upper element and protruding downwardly in order to perform the opening of the pincer against a bias spring force. Therefore, three-part device is relatively complex and expensive. DE-A-2 519 610 discloses a two-piece pincer comprising a fixed jaw and a movable jaw thrust to closure by means of a spring. In an intermediate position the movable jaw comprises a cam surface to open the pincer. Fixed and movable jaws are pivotally jointed by means of a bottom end of the movable jaw inserted in a slot of the fixed jaw. The object of the present invention is to embody a device that will satisfy the aforesaid requirements and is simple and economical to manufacture and highly dependable in use. This object is attained by a chain link of the type in which a plate is provided with a pincer for hauling-off a sheet material, said pincer comprising a fixed jaw and a movable jaw pivoted between each other and thrust to closure by means of a spring, the movable jaw comprising a cam thrusting surface for the opening of the pincer against the action of the spring, whereby the plate comprises enbloc a bracket extending laterally at right angle from the upper side of the plate, the free end of said bracket constituting in its upper side the said fixed jaw, the lower side of the bracket forming pivoting means for the movable jaw, the upper free end of the movable jaw passing through an aperture in the bracket and being bended so as to form the movable jaw, and between the movable jaw and the bracket being placed a thrusting spring for the closure of the movable jaw against the fixed jaw (such a chain link is known from DE-A-2 519 610), characterized by the fact that the lower side of the bracket is rolled up so as to form a seat for a pin parallel to the bracket and to the plate, the movable jaw being constituted by an L shaped element placed close to the said plate in order to have a first side of the L substantially parallel to the plate and a second lower side substantially parallel to the bracket, the first side of the L bringing lateral fins bended towards the plate so as to form a fork having a free end holed in order to receive the said pin in the seat thus furnishing said pivoting means between plate and L shaped element, said thrusting spring being placed between the lower side of the L shaped element and the bracket. The structural and functional characteristics of the invention, and its advantages over the known art, will become more apparent from an examination of the following description, referred to the appended drawings, which show an example of a chain link embodied in accordance with the innovative principles of the invention. In the drawings: Figure 1 is an enlarged perspective view of the chain link in question; and Figure 2 is an enlarged vertical section illustrating the same link as in Figure 1 after assembly, where the movable jaw of the pincer is shown in the open position by a dashed line. With reference to the drawings, the chain link according to the invention is indicated overall by 10 and one of its plates 11 features a pincer 12. The pincer 12 comprises a fixed jaw 13 on a bracket 14 formed enbloc from the plate 11, and a movable jaw 15 pivoted by means of a pin 16 to a seat 17, said seat also being formed enbloc from the plate 11 by the folding back on an extremity thereof. As can be clearly seen from the appended drawings, the movable jaw 15 extends through an aperture 18 in the bracket 14 and is embodied in a single piece comprising a fork 19, which is pivoted to the seat 17 through the agency of the pin 16, and a tongue 20 folded back under the fork 19. The numeral 21 indicates a spring passing through an oversized section of the fork 19 and acting between the tongue 20 and tooth 22 which is inclined from the bracket 14. The spring 21 provides thrust to maintain the movable jaw 15 in the position shown by a continuous line in Figure 2. For thus purpose, and as is clearly shown in the Figures, the spring 21 is retained laterally and guided by the cheeks of the fork 19 in order to prevent it from straying from the compressed working position. The opening of the movable jaw 15 in relation to the fixed jaw 13 so as to be in the open position shown by dashed lines in Figure 2, is effected by a cam means (not shown) acting on the tongue 20, against the action of the return spring 21, so as to cause the movable jaw 15 to rotate about the pin 16 in the direction of the arrow 23. It is noteworthy that the operating end of the jaw 15 moves away from the fixed jaw 13 with a rearward component of motion so that the edge of the film to be gripped can rest itself on the fixed jaw with a vertical movement and thus without interfering with the movable jaw. This means that extruded film, or other sheet material, can be laid on the brackets 14 of the chain type haul-off devices positioned proximally to the longitudinal sides of the film, or other sheet material, when the movable jaws 15 are thrust into the open position by the aforesaid cam means, after which the jaws 15 can be closed in a spontaneously automatic manner by relinquishment by the said cam means, so as to lock the sheet material on the fixed jaw 13. There is in this manner attained the object referred to in the introductory part of the specification, i.e. the embodiment of a haul-off device of remarkable simplicity and economy and highly dependable in use.

Claims: Chain link of the type in which a plate (11) is provided with a pincer (12) for hauling-off a sheet material, said pincer (12) comprising a fixed jaw (13) and a movable jaw (15) pivoted between each other and thrust to closure by means of a spring (21), the movable jaw (15) comprising a cam thrusting surface for the opening of the pincer against the action of the spring, whereby the plate (11) comprises enbloc a bracket (14) extending laterally at right angle from the upper side of the plate (11), the free end of said bracket (14) constituting in its upper side the said fixed jaw (13), the lower side of the bracket forming pivoting means (16, 17) for the movable jaw (15), the upper free end of the movable jaw (15) passing through an aperture (18) in the bracket (14) and being bended so as to form the movable jaw (15), and between the movable jaw (15) and the bracket (14) being placed a thrusting spring (21) for the closure of the movable jaw (15) against the fixed jaw (13), characterized by the fact that the lower side of the bracket is rolled up so as to form a seat (17) for a pin (16) parallel to the bracket (14) and to the plate (11), the movable jaw (15) being constituted by an L shaped element placed close to the said plate (11) in order to have a first side of the L substantially parallel to the plate (11) and a second lower side substantially parallel to the bracket (14), the first side of the L bringing lateral fins bended toward the plate (11) so as to form a fork (19) having a free end holed in order to receive the said pin (16) in the seat (17) thus furnishing said pivoting means between plate and L shaped element, said thrusting spring (21) being placed between the lower side (20) of the L shaped element and the bracket (14). Chain link according to claim 1, characterized by the fact that the spring (21) is provided with an upper end engaged to a tooth (22) folded back by said bracket (14), the spring (21) passing through an oversized section of said fork which retains it laterally. Chain link according to claim 2, characterized by the fact that the tooth (22) protrudes from a side of the bracket (14) close to the plate (11).

Inventors: GARBAGNATI CARLO, GARBAGNATI, CARLO
Applicants: REGINA IND SPA, REGINA INDUSTRIA S.P.A.
Application year: 1988
Main classification: B65H20
IPC codes: B65H29, B65H20