Device with automatic feeder for driving ribbon-mounted screws

Abstract: A device with automatic feeder for driving ribbon-mounted screws (V), comprising a guide (31) in front of which a box-like body is mounted so that it can slide longitudinally; moreover the body (11) has a shallow seat (17) for the sliding of the ribbon which is connected to a longitudinal hole (18) for positioning the first screw and for the longitudinal sliding of the shank of the screwing tool (2) and can be closed, in an upward region, by a sort of lid (22) which is pivoted to the body and can be locked by means of a sliding bolt (26) in the seat (17) covering position; that the seat (17) is crossed by a lower tooth (32) for retaining the first screw which is associated with a lever system; and that a spring latch (42) is mounted in the lid (22) and is actuated so as to oscillate.

Description: The present invention relates to a device with automatic feeder for driving ribbon-mounted screws. Conventional electric screwing tools are equipped with an automatic feeder that is adapted to work with screws that are mounted side by side on a ribbon made of a material such as plastics: in conventional loaders, the first screw to be driven is usually kept aligned with the screwing tool by acting on the second screw: usually the second screw is kept aligned by means of a tip element which, when the loader is pressed towards the part into which the screw must be driven, is in turn pressed against the tip of the second screw: it is thus impossible to drive the last screw at the end the ribbon (as there is nothing that could keep it aligned). Moreover, in conventional loaders, in order to reach the region where the ribbon slides and to adjust the driving depth and the length of the screw it is necessary to act on elements that must be operated with wrenches or in any case to carry out operations that require a considerable waste of time. From GB-A-2 132 531 it is known a device for feeding and driving screws as defined in the preamble of claim 1. From US-A-4 014 225 it is known a power-driven screwdriver in which a lid is provided to cover a ribbon which supports a plurality of screws to be fed under the screwdriver. A principal aim of the present invention is to obviate the described drawbacks of conventional devices, by providing a device with automatic feeder for driving ribbon-mounted screws that is capable of acting even on the last screw of the ribbon and in which it is possible to reach the ribbon sliding region and to perform the various adjustments without requiring tools and in a simple and quick manner. Within this technical aim, a further object of the present invention is to provide a device that is simple, relatively easy to provide in practice, safe in use, effective in operation, and relatively inexpensive. This aim and this further object are both achieved, according to the present invention, by the device as defined in claim 1. Further features will become clearly apparent from the following detailed description of a preferred but not exclusive embodiment of a device for driving ribbon-mounted screws with automatic feeder, according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein: figure 1 is a perspective view of a device for driving ribbon-mounted screws with automatic feeder according to the invention; figure 2 is a partially sectional cutout side view of the device; figure 3 is a partially sectional cutout bottom view of the device; figure 4 is a partially sectional cutout top view of the device; figure 5 is a sectional view, taken along the plane V-V of figure 4. With particular reference to the above figures, the reference numeral 1 generally designates a device, according to the invention, for driving ribbon-mounted screws with automatic feeder for a screwing tool 2, which is adapted to work with screws V that are mutually joined by a long ribbon N made of a material such as plastics. The device 1 comprises a guide 3 which ends, at one end (as shown in figure 1), with a flat front 4 that is crossed by a hole 5 provided with a slot 6 and a locking screw 7 that constitute means for mounting it in front of the screwing tool 2, which has a screwing shank 8 that ends with an interchangeable screw blade 8a; in alternative (figures 2, 3, 4, and 5), the flat front 4 is welded to the screwing tool 2 to form a monolithic body. In cross-section, the guide 3 is substantially shaped like a broad and flat letter U whose edges end with opposite ribs 9a, 9b that are adapted to cooperate with corresponding lateral slots 10a, 10b of a shallow box-like body 11 to allow the longitudinal sliding of the body 11. The front 4 has a stem 12 on which the end of a helical compression spring 13 is centered; the other end of said spring is inserted in a bush 14 for adjusting the driving depth: the bush 14 is screwed into a rear threaded hole 15 of the body 11, has an end 16 which has a larger diameter and is advantageously knurled for manual actuation, and is adapted to abut against the flat front 4 and act as stroke limiter for the backward motion of the body. The body 11 has a shallow seat 17 for the sliding of the ribbon N provided with screws V; said seat is connected, along one side, to a longitudinal hole 18 for positioning the first screw and for the longitudinal sliding of the shank of the screwing tool: the seat 17 has, towards the end that faces the screwing tool, a pair of slots 19a and 19b in which the heads of the screws V are accommodated, using one slot or the other depending on the size of the screws. The body 11 has, at the edge of the seat 17, a square recess 20 in which the centrally protruding end 21 of a sort of lid 22 can be snugly fitted: the recess 20 and the end 21 have corresponding holes and are crossed by a transverse pivot 23 so as to hinge the lid 22 to the body 11: the lid too has, on its lower face, transverse slots 24a and 24b that cooperate with the slots 19a and 19b to keep the screw heads guided. At its free end, the lid is crossed by a transverse hole for the stem 25 of a sliding bolt 26 that has an actuation lever 27 which protrudes from a front slot 28 of the lid and has a compression spring 29 that is adapted to push outward the stem 25 so that it enters a corresponding hole 30 of the body 11 to couple the lid to the body in the active configuration. The base of the seat 17 is crossed by a transverse slot 31 for the passage of a saw-tooth element 32 for retaining the first screw: below the seat, the saw-tooth element is rigidly coupled to a mushroom-shaped stud or pad 33 with a narrower central stem 34 which is associated with a lever system 35 whose end is pivoted to the body 11 by means of the pivot 36; elastic means, constituted by a coil spring 37 centered on the pivot 36, are adapted to keep said stud pressed in the direction of the arrow A; a profile 39 is fixed longitudinally to the guide 3 by means of a screw 38 and has, at the front, two contoured portions 40a and 40b which are adapted to act on the lever system to move the saw-tooth element (in the opposite direction with respect to the arrow A) below the second screw during the relative retraction (arrow B) of the body with respect to the guide during screwing and to move the second screw into the hole 18 (direction of the arrow A) during the relative advancement of the body 11 during the movement of the screwing tool away from the part into which the screw has been driven (in the opposite direction with respect to the arrow B): the ribbon N, freed of the screw, exits from the box-like body 11 through the lateral slot 18a of the hole 18 and also acts as element for centering and aligning the first screw in the hole 18; in order to compensate for the possible different types of ribbon, a plate 41 provided with a longitudinal positioning slot 41b is mounted in front of the slot 18 so that it can slide and be locked by means of a screw 41a. A spring latch 42 is mounted in the lid 22 and is actuated so that it can oscillate; said spring latch is shaped like a saw-tooth and is supported at the end of an arm 42a which is pivoted, by means of a pivot 43, in a seat 44 of the lid and is pressed by a helical compression spring 45 in the direction along which said spring latch protrudes from the lower face of the lid (arrow C): the spring 45 is accommodated in a seat of the lid that lies substantially at an angle with respect to the pivot 43 and presses against a small flat surface 46 of the arm of the spring latch; the spring latch 42 is adapted to stop the second screw while the first saw-tooth 32 passes beneath it and to allow the translatory motion of the second screw into the place previously occupied by the first screw. In order to avoid the spontaneous rotation of the bush 14, the threaded outer surface of the bush is affected by multiple flat facets against which a ball 47 can press; said ball is mounted so that it can move under the action of a compression spring 48 in a hole 49 of the box-like body which is closed by a grub screw 50. The sliding stroke of the body 11 along the guide 3 is limited by means of an elongated slot 51 which is formed longitudinally with respect to the guide and in which a pin 52 slidingly fits; said pin is mounted, so that it can slide axially, inside a hole 53 of the base of the body 11 and is pushed outward by a compression spring 54: at the end of the slot 51 there is a small hole 55 in which a pointed object can be inserted to retract the pin 52 and release the body 11. A screw magazine 56 is mounted on one side of the loader 2, is coupled to said loader by means of a bracket 57, and is substantially shaped like a drum with a horizontal axis at right angles to the vertical plane of arrangement of the shank 8; the ribbon N with the screws V exits from a front slot 58 of the magazine 56. Above the hole 18, the body 11 has a pyramid-shaped point 59 which visually indicates from above the point from which the screw V will exit. The operation of the device for driving ribbon-mounted screws with automatic feeder according to the invention has been presented in detail during the description. It should be noted that centering of the screw to be driven is provided on the screw itself (by means of the saw-tooth 32) and on the ribbon N (by means of the plate 41): the driving depth is adjusted by means of the bush 14, and adaptation to the various types of ribbon N is provided by means of the plate 41. It has thus been shown that the invention achieves the intended aim and objects. The invention thus conceived is susceptible of numerous modifications and variations within the scope of the invention as defined by the claims. In practice, the materials employed, as well as the shapes and dimensions, may be any according to the requirements without thereby abandoning the scope of the protection of the claims that follow. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims: A device with automatic feeder for driving ribbon-mounted screws (V) comprising a guide (3) which is provided with means (4, 5, 6, 7) for fitting it in front of a screwing tool (2), a box-like body (11) mounted on said guide (3) so as to be able to slide backwardly and forwardly on the guide (3) in the longitudinal direction of the driving shank (8) of the screwing tool (2), elastic means (13) being provided to urge the body (11) in direction away from the screwing tool (2), said box-like body (11) having a shallow seat (17) for slidingly supporting the ribbon (N) from below, the seat along one side thereof being contiguous with a hole (18) extending in longitudinal direction of the driving shank (8), the longitudinal hole (18) being adapted for receiving and positioning a first, forwardmost one of the screws mounted on the ribbon (N) and for receiving the driving shank of the screwing tool (2) in a manner allowing for the relative sliding movement between the body (11) and the guide (3) with the screwing tool (2), said seat (17) being crossed by a transverse slot (31) for the passage of a lower tooth of a tooth element (32) for retaining the first screw, said tooth element (32) being associated with a lever system (35) adapted to move the lower tooth of the tooth element (32) to a position below the second screw during the retractive movement of the body (11) relative to the guide (3) in direction towards the screwing tool (2) and to move the second screw into said hole (18) during the return stroke of the body (11), a lid (22) being provided which is pivotally connected to the body (11) so that it can be pivoted into an operative position, in which a lower surface thereof is opposite to the seat (17) and defines a cavity therewith through which the ribbon (N) can be fed in a lateral direction of the driving shank (8), and in which position it can be locked by means of a sliding bolt (26), the device further comprising a spring latch (42) resiliently urged into a position in which it protrudes into the trajectory of the screws in the ribbon (N), said spring latch (42) being offset with respect to the tooth element (32) and being adapted to retain a screw against movement in direction of backward movement of the ribbon and to allow translatory motion of the screws in feed direction of the ribbon (N), into the hole (18), characterised in that the spring latch (42) is mounted in said lid (22) and protrudes from a lower surface thereof, in that the spring latch is disposed to retain said second screw while the lower tooth of the tooth element (32) passes below it keeping it aligned, and in that tooth element (32) and said spring latch (42) have a saw-tooth shape, both the upper surface of the toothed element (32) and the surface of the spring latch element (42) which is faced downward being respectively inclined relative to the plane defined by the seat (17). A device according to claim 1, characterized in that a bush (14) for adjusting the driving depth can be screwed to the rear of said box-like body (11) and is adapted to abut against the end of said guide (3) and act as stroke limiter for the retraction of the body (11). A device according to claim 1, characterized in that said longitudinal hole (18) of the body for the sliding of the screw (V) and of the driving shank (8) of the screwing tool (2) has, on one side, a slot (18a) for the exit of the ribbon (N). A device according to claim 3, characterized in that a ribbon supporting plate (41) is adjustably mounted in front of said slot (18) in the body (11). A device according to claim 1, characterized in that said tooth element (32) is rigidly coupled to a pad (33) which is associated with the end of a lever system (35) whose end is pivoted to the body (11) and along which a longitudinal profiled element (39) slides, said profiled element (39) being rigidly coupled to said guide (3).

Inventors: ADAMO GIUSEPPE, ADAMO, GIUSEPPE
Applicants: NIKEMA SRL, NIKEMA S.R.L.
Application year: 1995
Main classification: B25B23
IPC codes: B25B23, B25C1