Feeder for components, in particular components designed with a head

Abstract: A Feeder for elongate components, in particular components designed with a head, has a feed tube with an inlet orifice which can be connected to a feed line and an orifice in the top region thereof and a gripper with at least two gripping arms (1) which are provided with a front gripping region (2) and a rear pivot axis region (3). The gripper is arranged in the feed tube which has, in its top region, a lower plane surface and an upper plane surface opposed to it; The gripping arms (1) each have a guide step (6) which preferably tapers and extends from the pivot axis region to the gripping region (2) on a longitudinal end face (5) turned toward the upper plane surface, the guide step (6) serving to guide the head of an elongate component; and The gripping arms (1) have, in the gripping region (2), a recess (7) adapted to the external shape of the elongate components to be gripped.

Description: The invention relates to a feeder for elongate components, in particular components designed with a head such as rivets, studs, pins, weld-in parts, which feeder has a feed tube with an inlet orifice which can be connected to a feed line and an orifice in the top region thereof and a gripper with at least two gripping arms which are provided with a front gripping region and a rear pivot axis region. Prior art feeders are used wherever cylindrical parts, for example, have to be supplied in large numbers to a further processing station as is the case, for example, in the car industry. Other known examples of these feeders include, for example, rivet setting tools. The feed rate is the critical point as it substantially determines the productivity of a production process. At high feed rates there is the risk with numerous feeders that components to be supplied will jam or will be supplied in a tilted manner. Therefore, a gripper for the components to be supplied is provided in feeders so that the components can be gripped and can be reliably placed on the further processing station. In known feeders, for example, the gripper is arranged outside a feed tube. The gripper consisting of two gripping arms rests on plane supports which, at the bottom, limit the feed chamber which is designed to taper between the gripping arms of the gripper. In their back region, the gripping arms have pivot pins which are inserted into holes in this support and allow pivoting of the gripping arms in order to open and close the gripper. The plane support is an integral part of a feed channel which is located in front of the pivot axes of the gripping arms in the conveying direction of the supplied parts and is limited by two vertical lateral walls but is open at the top. Therefore, the components to be supplied are able to escape upwardly and, under undesirable conditions, can leave the feed channel completely on the one hand or jam in it and make the supply of further components impossible on the other hand. The problem of tilting occurs mainly with those components which are to be supplied and are designed with a head, the dimensions of the head generally being greater than the shank dimensions. These components are, for example, rivets. However, to prevent the components which are to be supplied from tilting, it is necessary to reduce the feed rate of the components. However, this reduces the speed of the production process. It is accordingly the object of the present invention to provide a feeder with which jamming or tilting of the components to be supplied is avoided even at high feed rates. The present invention provides feeder for elongate components, in particular components designed with a head, which has a feed tube which is in a substantially horizontal orientation with an inlet orifice in the back region of the feed tube which can be connected to a feed line and a front outlet orifice in the top region thereof and a gripper with at least two gripping arms which are provided with a front gripping region and a rear pivot axis region, characterised in that a) the gripper is arranged in the feed tube which has, in its top region, a lower plane surface and an upper plane surface opposed to it; b) the gripping arms extend substantially horizontally in the tube; are disposed for pivotal movement substantially in a horizontal plane and protrude from the tube through the outlet orifice and each have a guide step which preferably tapers and extends from the pivot axis region to the gripping region on a longitudinal end face turned toward the upper plane surface, the guide step together with the space between the gripping arms serving to guide the head of an elongate component in an upright position towards the gripping region; and c) the gripping arms have, in the gripping region, a recess adapted to the external shape of the elongate components to be gripped, and disposed to receive the elongate components in a substantially verically extending direction. The gripping arms have a front gripping region in which the actual gripping process takes place and a rear pivot axis region which allows pivoting of the gripping arms in order to open and close the gripper. To enable the components which are to be supplied to be supplied as far as possible in a closed channel close to the actual gripping region of the gripping arms, the gripper is arranged in a feed tube. The gripping arms of the gripper of the feeder are preferably compressed by a spring arrangement in order to hold the supplied component before it is supplied to a further processing station or if it is to be held at the further processing station which can be, for example, a riveting station or a welding station. To prevent the components which are provided with a head and are to be supplied from being tilted in the gripping region, the recess in the gripping region of the gripping arms preferably has an enlarged region which serves to receive the head of the component. The guide step formed in the gripping arms in each case opens into this enlarged region of the recess. For reasons of assembly and exchangeability, the upper portion of the feed tube is divided. The upper portion of the feed tube forms an upper part of which the internal surface forms the upper plane surface in the substantially rectangular top region of the feed tube. The gripping arms have hinge pins in their pivot axis region. Two respective holes for receiving these hinge pins are arranged in the removable upper part and in the lower plane surface opposed to it. The gripping arms of the grippers can therefore perform a pivoting movement so on the one hand the arms open and close and on the other hand, in the closed state, the gripper can perform a movement permitting displacement of the gripped component in a plane perpendicular to its longitudinal axis. The opening movement of the gripping arms is limited by the other two internal lateral surfaces of the top region of the feed tube which is substantially rectangular in cross-section. The gripping arms are preferably designed so that they merely touch one another in the front region between the recess and the outer arm end in a state in which there is no component in the gripping region. In the feed tube, the gripping arms preferably have a tapering space extending from the pivot axis region to the gripping region for the supply of the components. The thickness of the gripping arms with respect to a plane perpendicular to the gripper axis decreases toward the gripping region but increases from a cross-sectional area in the longitudinal direction of the gripping arms such that the space tapers more markedly from this cross-sectional area than in the region following the pivot axis region in the direction toward the gripping region. To enable the feeder to perform precise adjustment or positioning of the part to be supplied to the further processing or arrangement station, the feeder co-operates with a plunger which on the one hand permits the introduction of the component to the further processing or fastening station and on the other hand performs adjustment in precisely the desired position. For this purpose, the gripping arms have a step on a front edge of the removable upper part, forming a higher front region of the gripping arms. This higher front region is offset at the outer ends of the gripping arms, more specifically by a width substantially corresponding to the width of the head of the elongate components. The head of the plunger which also has a centering function is designed such that, in the gripping state of the gripper, it fits into this offset of the front region of the gripping arms so that the lateral movement of the gripper in the feed tube, leading to decentering, is prevented. Further advantages, features and possible applications of the present invention are described with reference to an embodiment in conjunction with the drawings. Figure 1 shows a feed tube with gripper and plunger according to the present invention. Figure 2 shows a gripping arm of the gripper according to the present invention. Figure 1 shows an advantageous embodiment of a feeder according to the present invention. The feeder consists of the feed tube 14 having an inlet orifice 17 provided on a hose advantageously for pneumatic conveyance of the components to be supplied and a front outlet orifice 18. The feed tube 14 receives the gripper in its interior. For this purpose, the top region of the feed tube 14 has a removable upper part 15, 16 which forms the upper plane surface of a substantially rectangular cross-section in the interior of the top end of the feed tube 14. In the removable upper part 15, 16 and in the lower plane surface opposed to its interior there are provided two respective holes which serve to receive pivot pins or hinge pins 9 located in the pivot axis region 3 of the gripping arms 1. A piece 16 of the removable upper part 15, 16 projects with respect to the outlet orifice 18 of the feed tube 14 and therefore extends directly adjacently to the gripping region of the gripping arms 1. The feed channel formed in the space between the gripping arms of the gripper and the upper plane surface is therefore closed so that the head of the component to be supplied cannot issue from the channel. Tilting of the component to be supplied is therefore ruled out even at high feed rates. Figure 2 shows an individual gripping arm 1. The gripping arm 1 has a gripping region 2 and a pivot axis region 3. In the gripping region 2 there is provided a recess 7 which substantially corresponds to the external shape of the component to be supplied. To allow great flexibility with respect to the shape of the components to be supplied, the recess can also have longitudinal grooves of any shape in the axial direction of the component to be supplied so angular components can also be reliably gripped and held. The gripping arms 1 are spring loaded from the exterior so they are invariably compressed. Only the gripping arm ends make contact in the component-free state. In the upper region, the gripping arms 1 have a guide step 6 which faces the upper plane surface of the feed tube 14, is machined obliquely and tapers from the pivot axis region 3 toward the recess 7 of the gripping region. The upper region of the recess 7 of the gripping region of the gripping arms 1 has an enlarged region 8 into which the guide step 6 opens. The guide step 6 serves for the reliable supply of an elongate component provided with a head into the gripping region 2 through the space formed between the gripping arms 1. This space tapers more markedly forwardly in the direction of the gripping region 2 from a specific portion 11 of the gripping arms 1 than in the region before it with respect to the feed direction of the component to be gripped. As a result, the component is snapped into the recess 7 in the gripping arms 1 subjected to spring tension and is held there owing, among other things, to the moment of inertia during supply. The components which are supplied individually at high speed, preferably pneumatically, initially press the gripping arms 1 apart, are decelerated in the process and then come to a standstill precisely in the recess. With respect to the projecting piece 16 of the removable upper part 15, 16 of the feed tube 14, the gripping arms 1 have a step 12 which extends close to the front edge of the projecting region 16 but still allows a lateral movement of the gripping arms 1 round the pivot axis without contacting this front edge. At the outer ends of the gripping arms above the enlarged region 8 there is also machined a centering step 13 in which a plunger 4 assuming a centering function can engage. This plunger 4 enables the component which is to be supplied to be positioned precisely in the supply station. The component to be supplied is pressed out of the recess 7 in the gripping region 2 of the gripping arm 1 by the plunger 4 against the effect of the spring force.

Claims: Feeder for elongate components, in particular components designed with a head, which has a feed tube (14) which is in a substantially horizontal orientation with an inlet orifice (17) in the back region of the feed tube which can be connected to a feed line and a front outlet orifice (18) in the top region thereof and a gripper with at least two gripping arms (1) which are provided with a front gripping region (2) and a rear pivot axis region (3), characterised in that a) the gripper is arranged in the feed tube (14) which has, in its top region, a lower plane surface and an upper plane surface opposed to it; b) the gripping arms (1) extend substantially horizontally in the tube (14); are disposed for pivotal movement substantially in a horizontal plane and protrude from the tube (14) through the outlet orifice (18) and each have a guide step (6) which preferably tapers and extends from the pivot axis region to the gripping region (2) on a longitudinal end face (5) turned toward the upper plane surface, the guide step (6) together with the space between the gripping arms (1) serving to guide the head of an elongate component in an upright postion towards the gripping region; and c) the gripping arms (1) have, in the gripping region (2), a recess (7) adapted to the external shape of the elongate components to be gripped, and disposed to receive the elongate components in a substantially verically extending direction. Feeder according to Claim 1, characterised in that the gripping arms (1) can be compressed by a spring in order to hold the supplied component. Feeder according to Claim 1 or 2, characterised in that the recess (7) which corresponds to the shape of the components to be gripped has an enlarged region (8) for receiving a head of the component in which the guide step (6) opens. Feeder according to Claim 1, characterised in that the feed tube has a removable upper part (15, 16) in the top region. Feeder according to one of Claims 1 to 4, characterised in that the gripping arms (1) have, in the pivot axis region (3), hinge pins (9) which are pivotal around a pivot axis in two respective holes in the upper plane surface forming the interior of the top region of the feed tube and in the lower plane surface opposed to it. Feeder according to one of Claims 1 to 5, characterised in that the gripping arms (1) contact one another in the front region between the recess (7) at an outer end of the gripping arms when the gripping region (2) is free from components. Feeder according to one of Claims 1 to 6, characterised in that the gripping arms form a tapering space for the supply of the component from the pivot axis region (3) to the gripping region (2). Feeder according to Claim 7, characterised in that the thickness of the gripping arms increases in the direction of the gripping region from a portion (11) in the longitudinal direction of the arms (1) so the space tapers more markedly from this portion (11) than in the region following the pivot axis region (3) in the direction of the gripping region (2). Feeder according to Claim 4, characterised in that the gripping arms (1) are provided with a step (12) on a front edge of the removable upper part (15, 16) so a higher front region of the gripping arms (1) is formed, this higher front region being offset in the form of a step as a centering step (13) at the outer ends of the gripping arms, more specifically by a width substantially corresponding to the width of the head of the elongate components, for receiving a plunger (4) performing a centering function. Feeder according to Claim 4 or 10, characterised in that a piece (16) of the removable upper part (15, 16) projects beyond the edge of the feed tube (14) and is sufficiently wide to cover the space between the two gripping arms (1) in any position of the gripping arms, in particular rests almost tightly thereon.

Inventors: KNETSCH HARALD, KNETSCH, HARALD
Applicants: EMHART INC, EMHART INC.
Application year: 1995
Main classification: B25B23
IPC codes: B65G47, B23P19, B65G51