Patent Publication Number: US-3875982-A

Title: Fastener feeding apparatus drive control means

Description:
United States Patent 11 1 Mizu et al.  
 [ Apr. 8, 1975 1 1 FASTENER FEEDING APPARATUS DRIVE CONTROL MEANS [73] Assignee: Matsushita Electric Industrial Co.,  
 Ltd., Osaka, Japan 221 Filed: Nov. 20, 1973 21 Appl. No.: 417,529  
 [30] Foreign Application Priority Data [58] Field of Search 221/9, 10; 144/32; 29/211, 29/240; 227/114, 116  
 [56] References Cited UNITED STATES PATENTS 3,265,273 8/1966 .lanus 227/116 X 3,305,155 &#39;2/1967 Willis 1 1 227/116 3,583,451 6/1971 Dixon 144/32 3,642,039 2/1972 McGee 144/32 3.779.422 12/1973 Mori ct al. 221/10 Primary E.\&#39;aminerAndrew R. .luhasz Assistant ExaminerW. D. Bray Attorney, Agent, or FirmWender0th, Lind and Ponack 57 ABSTRACT A drive control means by which headed parts such as screws or other fasteners contained in any order in a bulk supply means such as a hopper are supplied continuously in a required alignment to a distributor, and supplied individually from the distributor to a power operated fastening tool. The drive control means has sensing elements which detect when the fastening tool requires a fastener to be supplied thereto, and actuates the distributor to supply a fastener accordingly, and which detect the state of supply of fasteners to the distributor, and actuate a means to supply fasteners from the bulk supply means only when necessary, whereby a constant reserve is maintained in readiness for immediate supply to the distributor and to the fastening tool. The entire drive control means is operated from a single source of pneumatic power, and may be used directly in association with feeding apparatus for fasteners of different sizes.  
 6 Claims, 23 Drawing Figures PATENTEDAPR 8 I915 SHEET [11 OF H PATENIEDAPR 8l97 5 SHEET 0 [1F 11 FIG. 7  
 PATENTEDAPR 8 I975 SHEET B50? 11 FIG. 8  
 PATENTE 8W5 3.875.982  
 - sum new 11 53 7 pwwa gzb PATENTEDAPR 8191s 3.875.982 SHEET 07m 11 FIG.  
 PATENTEUAPR&#39; ems SHEET 08 0F 11 FIG. /4  
 PATENTEDAPR ems SHEET [38 8F 11 FIG. 16  
 PATENTED 9 5 SHEET mm H 3.875.982  
 FIG. /8  
 FASTENER FEEDING APPARATUS DRIVE CONTROL MEANS The present invention relates to a drive control means, and more particularly to a pneumatic drive control means for automatically effecting a continuous supply of individual fasteners, such as screws, or rivets, to a required fastening device.  
  Fastening operations by means of screws, rivets, or similar elements are carried out on a large scale in many branches of industry. To facilitate and speed up such fastening operations it has been known to employ a means for automatic feed of individual fasteners to a power operated screwdriver, or similar fastening device. Such automatic feed means must to be controlled by a drive control means which is accurate and reliable, and which ensures that fasteners are delivered to a fastening device in accordance with the needs of the fastening device, is, that as soon as the fastening device has attached one fastener to a required object, another fastener is rapidly supplied thereto, in readiness for the next fastening operation. Conventional drive control means make combined use of electrical power and pneumatic power in order to effect control of automatic fastener feed. This combined use of two different sources of power has the evident disadvantages that the drive control means as a whole is made more complex, and as well as being initially expensive, is also less reliable, since there are two possible sources of failure.  
  It is accordingly an object of the invention to provide a drive control means which employs only a pneumatic power source, and whereby fasteners, such as screws, or rivets, are supplied continuously from a bulk supply means to a distributor, and fed individually from the distributor to a fastening device, in accordance with the needs of the fastening device.  
  It is another object of the invention to provide a drive control means whereby a removal means such as a rotarydrum, is actuated to remove fasteners from a bulk supply means, such as a hopper, only when such removal is necessary to maintain a constant supply of fasteners to a fastening device, thereby raising efficiency and reducing running costs of an automatic feed means.  
  It is a further object of the invention to provide a drive control means comprising one or more low airpressure detection means for the detection of the state of supply of fasteners or other objects on a feed line.  
  It is a still further object of the invention to provide a drive control means which is adaptable directly, and unchanged, to control of automatic feed systems for objects of different sizes, thereby rendering unnecessary the purchase of different automatic feed means for feed of objects of different sizes.  
  In accomplishing these and other objects, there is provided, according to the present invention, a drive control means comprising first and second pneumatic circuits, air being supplied to both circuits from a single source, the first circuit being for the control of a rotary drum which removes fasteners from a bulk-storage hopper and onto a feed chute leading to distributor, and the second circuit effecting control of the individual distribution of fasteners to a fastening device. The first circuit comprises a sensing means which detects the amount of fasteners on the chute leading to the distributor, and gives a signal to actuate the drum to feed fasteners onto the chute when there is less than a certain number of fasteners on the chute, and otherwise gives a siganl to cease actuation of the drum. The second circuit comprises a sensing means which detects when the fastening device requires a fastener to be fed thereto, and at this time gives a signal causing the distributor to transmit a fastener to the fastening device, and otherwise gives a signal causing the distributor to remain unactuated.  
  A better understanding of the present invention may be had from the following full description taken in conjunction with several preferred embodiments thereof with reference to the accompanying drawings, in which like numerals refer to like parts, and in which;  
  FIG. 1 is a schematic perspective view of a fastener feeding apparatus controllable by a drive control means according to the present invention;  
  FIG. 2 is a similar view to FIG. 1, but showing the apparatus viewed from a different position;  
  FIG. 3(a) is a side view of a rotary drum showing linkage between the drum and an air cylinder;  
  FIG. 3(b) is a front elevational view of the drum of FIG. 3(a);  
  FIG. 3(c) is an enlarged view of a pawl portion of the linkage shown in FIG. 3(a) and 3(b);  
  FIG. 4 is an enlarged, perspective view of a sensing and signal means for detecting the presence of fasteners on a chute;  
  FIGS. 5(a) and 5(b) are vertical cross-sectional views of the sensing and signal means shown in FIG. 4;  
  FIG. 6 is a perspective and partially sectional view of a fastener distributor;  
  FIG. 7 is a perspective view of a power operated fastening device;  
  FIG. 8 is an exploded view of a signal means associated with the fastening device shown in FIG. 7;  
  FIGS. 9(a) and 9(b) and 10(a) and 10(b) are partial plan and cross-sectional views, respectively, illustrating operation of the fastening device signal means;  
  FIG. 11 is a circuit diagram of air flow in a drive control means according to one embodiment of the invention;  
  FIG. 12 is a perspective view of a fastener feeding apparatus associated with a second embodiment of the invention;  
  FIG. 13 is a similar view to FIG. 12, but showing the apparatus viewed from a different position;  
  FIG. 14 is a perspective and partially sectional view of a fastener distributor;  
  FIG. 15 is a schematic cross-sectional view of the fastener distributor shown in FIG. 14;  
  FIG. 16 is a perspective view of a power operated fastening device;  
  FIG. 17 is a cross-sectional view of a signal means associated with the fastening device shown in FIG. 16; and  
  FIG. 18 is a circuit diagram of air flow in a drive control means according to a second embodiment of the invention.  
  Referring initially to FIGS. 1 and 2 there is shown an example of a feed means, automatic control of which may be suitably effected by a drive control means according to the invention. The feed means comprises a generally basin-shaped, open-topped hopper 2, in which fasteners, such as screws, rivets, or similar objects, may be loosely held. The hopper 2 is fixedly supported in a raised position by generally vertical legs la and lb of a frame 1, which are fixedly attached to forward and rear portions of the hopper 2. The frame 1 further comprises a cross-piece 10, extending from the leg 1a to the leg 1b, and is itself fixedly mounted on a baseboard 23, which may optionally, in accordance with different requirements, be provided with screwholes, or other attachment means, for securing thereof to a floor, or other support. A rotary drum 3 is provided partially within, or constituting one side of the hopper 2. The drum 3 is rotatably mounted in a generally vertical alignment, that is, the rotational axis thereof is generally horizontal, and the top of the hopper 2 lies generally level with the center line of the drum 3. The drum 3 is rotatably mounted on, and supported by a shaft 7a see FIG. 3(b) extending horizontally from the top of a vertically-aligned support bracket 5. The lower portion of the drum support bracket 5 lies below the bottom of the drum 3, and is fixedly attached to the top portion of a vertically-aligned support plate 15. The plate 15 is fixedly attached to the frame 1. Drive to the drum 3 is supplied from an air cylinder 6, acting through a cylinder rod 12, block 11, linkage arms 9a, 9b, a and 10b, pawls 8, and a ratchet wheel 7. The air cylinder 6 is actuated by a reciprocating unit 13, which is mounted on the frame 1 and is described in further detail below. The ratchet wheel 7 is mounted on the shaft 7a and is fixed&#39;coaxially to the drum 3, whereby rotation of the ratchet wheel 7 causes rotation of the drum 3. The block 11, rod 12, and cylinder 6 are all in a generally vertical alignment below the ratchet wheel 7. The air cylinder 6 rests on the baseboard 23, and the upper end thereof is supported by a bracket 14, which extends from, and is fixedly attached to, or integrally formed with, the support plate 15. Control of air to the reciprocating unit 13 and air cylinder 6, and to and from other parts of the drive control means of the invention, is effected by a control box 22, which is mounted on the frame 1.  
  Referring now to FIGS. 3(a), 3(b) and 3(c) the block 11 is fixedly mounted on the upper end of the rod 12. The lower end of the rod 12 connects to the piston (not shown) of the air cylinder 6 whereby actuation of the air cylinder 6 causes the rod 12 and block 11 fixedly attached thereto to move reciprocally upwards and downwards. The linkage arms 9a and 9b are slightly greater in length than the radius of the ratchet wheel 7, and are rotatably mounted at one end on the shaft 7a. The linkage arms 10a and 10b are slightly less in length than the radius of the drum 3, and the lower ends thereof are rotatably attached, through a pin 25, to the block 11. The upper ends of the linkage arms 10a and 10b are rotatably attached, through pins 24a and 24b, to the outer ends of the linkage arms 9a and 9b respectively. The abovementioned pawls 8a and 8b also are rotatably mounted on the pins 24a and 24b, respectively, and adjacent to the periphery of, and engageable with the ratchet wheel 7. Each pawl 8a and 8b is elastically held in an alignment for engaging the ratchet wheel 7 by a compression spring 27, opposite ends of which are fixedly attached to pins 26 extending from the facing sides of the pawl 8a and linkage arm 9a, or pawl 8b and linkage arm 9b. The pawls 8a and 8b are both inclined in the same direction with respect to the ratchet wheel 7, but lie on opposite sides thereof. Therefore, during reciprocal motion of the piston of the air cylinder 6, when the rod 12 and block 11 are moved upwards, the pawl 8a engages the ratchet wheel 7, thus rotating the ratchet wheel 7 and drum 3,  
 whereas the pawl 8b simply rides on the outer periphery of the ratchet wheel 7. Contrariwise, when the rod 12 and block 11 are moved downwards, the ratchet wheel 7 is engaged and rotated by the pawl 8b, and is not engaged by the pawl 8a. In both cases of engagement, however, whether by the pawl 8a or by the pawl 8b, the ratchet wheel 7, and hence drum 3, is rotated in the same direction, whereby reciprocal action of the air cylinder 6 produces unifrom rotary motion of the drum 3.  
  Referring back to FIG. 1, the drum 3 is rotated upwards towards the rear of the hopper 2, and downwards towards the front thereof. Around the periphery of the inside of the drum 3, there is provided a plurality of scoops 4, which are so shaped, and so inclined relative to the periphery of the drum 3, as to be able to scoop up fasteners lying loosely in the hopper 2, and carry the fasteners to the highest point of rotation of the drum 3. At this point, as the scoops begin to move downwards, fasteners carried therein, are discharged therefrom, onto a downwardly inclined guide tray 17. The guide tray 17 is located approximately vertically above the center of the hopper 2, and guides fasteners coming from scoops 4 into a downwardly inclined chute 16. The chute 16 comprises a pair of parallel boards 16a and 16b, and extends from the guide tray 17, through the front of the hopper 2, to a distributor 18, which is located below the level of, and forward of the hopper 2. The boards 16a and 16b are separated by a distance such that the head of a fastener 38 will be supported on the upper edges thereof, as most clearly shown in FIG. 5(a), whereby fasteners 38 will slide down the chute 16, in a correct alignment, to the distributor 18. Above the chute 16, and just before the point of exit thereof from the hopper 2. there is provided a rotatable rejector wheel 19. Fasteners 38 coming from the guide tray 17 which are not in a correct alignment, contact, and ride on the rejector wheel 19, and are returned thereby to the hopper 2. Fasteners 38 in a correct alignment pass under the rejector wheel 19. Those portions of the boards 16a and 16b lying outside, and forward of the hopper 2 are supported on suitably inclined support arms 21a and 21b, which extend from the support frame 1, and are integrally formed therewith. The arms 21a and 21b also provide support, or points of attachment, for a sensing means comprising a detection blower 20 and signal emitters 28 and 29, as most clearly shown in FIG. 4.  
  Referring now to FIGS. 4, 5(a and 5(b), the detection blower 20 may be seen to comprise a board 20a, which lies above, and is generally parallel to a lower portion of the chute l6, and in which there is formed a channel 30, through which air may pass. Air coming from an air compressor AC is supplied into the channel 30 by a pipe 31, which is attached to, and is external to the board 20a. Air leaves the channel 30 through nozzles 32a and 32b. As shown most clearly in FIG. 5, the nozzles 32a and 32b lie directly above the chute 16, and are so inclined that air coming therefrom is directed downwards between the boards 16a and 16b. The nozzle 32a lies above a higher point of the chute 16 than the nozzle 32b. Still referring to FIGS. 4, 5(0) and 5(b), the signal emitters 28 and 29 are situated directly below the nozzles 32a and 32b, respectively. The signal emitters 28 and 29 are identical in construction, and the description will proceed below in reference to the signal emitter 28 only, it being understood that the description is equally applicable to the signal emitter 29.  
  The signal emitter 28 as in the shape of a generally yoke-shaped element comprising two block portions&#34; 28a and 28b, which are attached by a strip portion 28c, and between which there is a gap 33a. In the block portions 28a and 28b there are formed passages 34a and 35a, respectively, or air. The air passages 34a and 35a, comprise generally horizontal portions which communicate with the gap 33a, and portions leading downwards to the bottoms of the block portions 28a and 28b, respectively. The horizontal portions of the air passages 34a and 35a, are aligned with one another, whereby air coming from the air passage 34a is directed into the air passage 35a, as described in further detail below. Connection pieces 36a and 36b are fixedly inserted in and project from the downwards portions of the air passages 34a and 35a, respectively. Air conduits 36a and 37a are fixedly attached to the connection pieces 36a and 37a, respectively. The signal emitter 29 similarly comprises block portions 29a, 29b, connecting strip 29c, and gap 33b, in a generally yoke-shaped element, air passages 34b and 35b, connection pieces 36b and 37b, and air conduits 36b and 37b. The air conduits 36a and 36b connect to a main supply line leading from the air compressor AC. The air conduits 37a and 37b connect to control input ports 78A and 78B of a NOR element 78, respectively as described in further detail below in connection with FIG. 11.  
  Referring more particularly to FIGS. 4, 5(a) and 5(b), air coming from the air compressor AC, passing through the air passage 34a or 34b, traversing the gap 33a, or 33b, and entering the corresponding air passage 35a or 35b constitutes an interruptable jet which may be interrupted by air directed by the nozzle 32a, or 32b, downwards between the boards of the chute 16. In FIG. 5(b), presuming there are no fasteners 38 on the chute 16, the air jets of both the signal emitters 28 and 29 are interrupted by air from the nozzles 32a and 32b, respectively, and therefore there is no output from either of the signal emitters 28 and 29. If the number of fasteners 38 on the chute 16 is such that the chute 16 is filled thereby from the bottom of the chute 16 to the location of the lower signal emitter 29, the presence of a fastener 38 between the nozzle 32b and the chute 16 prevents air from the nozzle 32b from interrupting the jet across the gap 33b of the signal emitter 29, as illustrated in FIG. 5(a). The signal emitter 29 accordingly produces an output, along the conduit 37b to the NOR element 78. (See FIG. 11.) Similarly, the upper signal emitter 28 produces an output, if fasteners 38 on the chute 16 extend to the location of the signal emitter 28. Referring now to FIG. 6, the bottom end of the chute 16 is fixedly attached to a fixed board 41a in the abovementioned distributor 18 by connector boards 40. The distributor 18 comprises a main housing 41, a fixed block 48, which is fixedly attached to the rear board 41a of the housing 41, and a slide block 44, which is slidable between the fixed block 48 and main housing 41. Within the main housing 41 there is formed a cylinder 42, which is generally at right-angles to the longitudinal axis of the chute 16. Cylinder heads 46 and 47 are provided on the exterior of the main housing 41, at opposite ends of the cylinder 42. A spring-loaded plunger 43 is slidably mounted in the cylinder 42. A spring 42a mounted in the cylinder 42 and on theplunger 43 normally urges the plunger 43 to take up a position in which one end 43a thereof projects beyond the outer side of the cylinder head 46 and is external to the main housing 41. In the fixed block 48, a little removed from the junction of the.block 48and chute 16, there is formed a fastener guidepassage 39 which extends downwards to, and communicates with one end of a connection piece 49. The other end of the connection piece 49 is connected to a distributor pipe 50. The distributor pipe 50 leads to a feed-in pipe portion 57 of a power-operated fastening device 51 (described below). One end of the slider block 44 is fixedly connected, through a connection plate 45, to the outer end 43a of the plunger 43, whereby movement of the plunger 43 in the cylinder 42 causes the slide bar 44 to move laterally with respect to the bottom end of the chute 16. In the slide bar 44 there is formed a cut-out portion 44a, which is of suitable dimensions for the accommodation of one fastener 38. When the plunger end 43a is normally extended outwards with respect to the main housing 41, due to the connection through the connection plate 45, the slide block 44 is carried to a position in which the cut-out portion 43a lies exactly opposite the bottom of the chute 16, whereby a lowermost fastener 38 in the chute 16 may leave the chute 16 and enter the cut-out portion 44a.  
  The main housing 41 also has an inlet which communicates through a normally closed switch valve B2 to a main air supply from the air compressor AC. The switch valve B2 is opened by input air coming from one outlet port 81 F1 of a bistable element 81 (described below in connection with FIG. 11.). When the switch valve B2 is thus opened flow of air from the main supply acts on the plunger 43, to cause the plunger 43 to move inwards with respect to the main housing 41, and at the same time a portion of this flow of air is supplied to the fastener guide passage 39. When the plunger 43 is thus moved inwards, the slide block 44 is carried to a position in which the cut-out portion 440 comes into alignment with the guide passage 39, whereby a fastener 38 having left the chute 16 and entered the cutout portion 44a is carried to the guide passage 39, guided therethrough to the connector piece 49, and thence through the distributor pipe 50 and feed-in pipe portion 57, into the fastening device 51. When the valve B2 is closed, the air supply to the distributor 18 is cut, and the plunger 43 and slide block 44 are returned by the force of the spring 420 to the original position in which the slide block cut-out portion is in line with the bottom of the chute 16, and can receive the next fastener 38, as shown in FIG. 6.  
  In reference now to FIG. 7, the fastening device 51 comprises a main unit 54 and a slide shaft 55 which is slidably mounted in the main unit 54, and is normally held in a forwardly extended position relative thereto by a spring 56. The abovementioned feed-in pipe portion 51 feeds fasteners 38, one at a time, into line with an outlet hole 58 at the forward end of the fastening device 51. A handle 59 is attached to the fastening device 51, to facilitate manipulation thereof. The fastening device 51 is also provided with conventionally known means for actuating a driver 83, which extends along the longitudinal axis of the fastening device 51 to the vicinity of the outlet hole 58, and which screws, or otherwise attaches, fasteners 38 to external objects. The fastening device 51 is actuated ina conventionally known manner, and uponactuation thereof, theslide I shaft 55 is slid into themain unit 54, against the force of the spring 56. A signal emitter 52 having a cover plate 77 is attached by means of screws 53a and 53b to the side of the main unit 54. A dog 62 is fixedly attached to the rear end of the slide shaft 55. The dog 62 contacts and actuates a hook element 70, which cntrols the movement of a swivel block 68, in the signal emitter 52, as shown in FIGS. 9(a) and 9(b).  
  Referring now to FIGS. 8, 9(0), 9(b), (a) and 10(b), the signal emitter 52 comprises a portion forming a cylinder 63. An air inlet 60 and an air outlet 61 are provided near one end 63a of the cylinder 63. The inlet 60 and outlet 61 are aligned with one another, and connect respectively to the control port 79A of a monostable element 79, and to a line P4 leading to the main air supply from the air compressor AC, as shown in FIG. 1 l. A spool 64 is slidably housed in the cylinder 63. One end of the spool 64 is in the form of an extension 66, which extends out of the cylinder 63 beyond the other end 63b thereof. Near the other end of the spool 64, inside the cylinder 63, there is formed an air passage 67, which is radial with respect to the spool 64, and extends completely therethrough. The spool 64 is spring-loaded by a spring 65, which exerts a constant force urging the spool 64 towards the end 63b of the cylinder 63, and into a position in which the air passage 67 is remote from the air inlet 60 and outlet 61, whereby air does not pass from the inlet 60 to the outlet 61, as shown in FIG. 9 (b).  
  The spool extension 66 is contactable by the abovementioned swivel block 68. The swivel block 68 is generally rectangular, and is rotatably mounted on a pin 69, which passes through a generally central point of the block 68. One end of a compression spring 72 is fixedly attached to a pin 73a, which is fixedly attached to a point on one half 68a of the block 68. The other end of the spring 72 is fixedly attached to a pin 73b, which is fixedly attached to a solid portion 74 of the signal emitter 51. The spring 72 exerts a constant force urging the swivel block 68 to turn about the pin 69 in such a manner that the other half 68b thereof presses against the spool extension 66, as shown in FIG. 10 (a). In this configuration, the spool 64 is forced to move inwards with respect to the cylinder 63, against the force of the spring 65, and into a position in which the air passage 67 formed therein comes into alignment with the air inlet 60 and outlet 61, whereby air can pass from the inlet 60 to the outlet 61, as shown in FIG. 10 (b).  
  The alignment of the swivel block 68 is not, however dependent uniquely on the force exerted by,the spring 72, but is also determined by the position of the abovementioned hook element 70. The hook element 70 is slidably supported on a plate 76, and comprises hook ends 70a and 70b, a main portion 700, and a block portion 70d. The main portion 70c is generally parallel to the longitudinal axis of the fastening device 51. The block portion 70d is fixedly attached, or integrally formed with the main portion 700, and extends towards and contacts the outer edge of the half 68a of the swivel block 68. The hook ends 70a and 70b extendat approximately right-angles from the main portion 700 and towards the fastening device 51, the hook end 70a being nearer the front end of the fastening device 51, and the hook end 70b being nearer the rear end thereof (FIGS. 9 (b), 10 (b)). When the slide shaft 55 of the fastening device 51 is in a normal forwardly extended position relative to the main unit 54, that is, during non-use of the fastening device 51, the dog 62 attached to the rear end of the slide shaft 55 contacts and pushes the hook end 700, whereby the hook element is moved slightly&#39;forwards, the block portion 700&#39; contacting the swivel block 68 aids the spring 72, and the block 68 is turned in such a manner that the half 68b thereof pushes the spool extension 66, and causes the spool 64 to move rearwards into a position in which the air passage 67 is in line with the air inlet 60 and outlet 61, as shown in FIGS. 10(a) and 10(b). In other words, during non-use of the fastening device 51, there is communication between the signal emitter air inlet 60 and outlet 61.  
  When the fastening device 51 is in operation, the slide shaft 55 moves inwards with respect to the main unit, and in this case, the dog 62 contacts and pushes the hook end 70b, whereby the hook element 70 is moved slightly rearwards. The hook element block portion 70d therefore causes the swivel block 68 to swivel against the force of the spring 72, whereby the block half 68b is moved out of contact with the spool extension 66 (FIG. 9 (a)), and the spool 66 is moved by the force of the spring 65 towards the forward end 63a of the cylinder 63, and into a position in which the air passage 67 in the spool 66 is remote from the air inlet 60 and outlet 61 (FIG. 9 (b)). In other words, when the fastening device 51 is in use to attach a fastener 38 to an external object, air cannot pass from the inlet 60 to the outlet 61. During use of the fastening device 51, air pressure at the inlet 60 builds up, and subsequently acts to trigger the monostable element 79 (described below) when use of the fastening device 51 terminates, and communication is again established between the inlet 60 and outlet 61.  
  Reference is now had to FIG. 11, in which there is shown a circuit diagram of fluid paths in a drive control means according to a first embodiment of the invention. In the drawing, the chain-dot line portion indicated generally by 22 corresponds to the control box 22 mounted on the frame 1, and other previously described elements are schematically represented by corresponding numbers.  
  Air for the entire circuit is initially supplied from the air compressor AC, or any other suitable means, at a pressure of 4 5 kg/cm. The air supplied first passes through a filter F1, and then divides into two paths leading respectively to a first control circuit, which controls supply of fasteners 38 from the hopper 2 to the distributor 18, and a second control circuit which controls distribution of fasteners 38 from the distributor 18 to the fastening device 51.  
  After passing through the filter Fl, air divides and passes through a regulator R1 or through an oiler 01. Air which has passed through the oiler 01 contains oil for the lubrication of various mechanical parts, and is supplied along a line P3 connecting to the fastening device 51, and along a line P6 connecting to a switch valve Bl, which is spring-loaded in a normally closed position, and which connects to an oscillator 82 contained in the abovementioned reciprocating unit 13 (FIG. 2). The valve B1 is opened by output supplied along a line P8, from an output port 80F 2 of a bistable element 80.  
  The oscillator 82 has two compartments, an upper compartment 82a and a lower compartment 82b, and is movable to two positions, an upper position U and a lower position L. Presuming the valve B1 &#39;is open, whenthe oscillator 82 is in the lower position L the upper compartment 82a thereof provides a connection between the line P6 and a lower pipe 612&#39; connecting to the air cylinder 6. When air is supplied through the lower inlet pipe 6b the piston of the air cylinder 6 is raised, and at the same time, a portion of this inlet air is led through a feedback line 6b to apply pressure to raise the oscillator 82 to the upper position U. Air is exhausted from the cylinder 6 through an upper pipe 6a connecting thereto. When the piston reaches a topmost position the pressure of air through the feedback line 6b becomes sufficient to raise the oscillator 82 to the upper position U. When the oscillator 82 is in the upper position U, the lower compartment 82b thereof provides a connection between the line P6 and the upper pipe 6a. Air supplied through the upper inlet pipe 6a causes the piston of the air cylinder 6 to move downwards, air being exhausted from the cylinder 6 through the lower pipe 612, and at the same time a portion of this inlet air is led through a feedback line 6a to apply pressure to move the oscillator 82 to the lower position L. When the piston of the air cylinder 6 reaches a lowest position, the pressure of air supplied through the feedback line 6a becomes sufficient to move the oscillator 82 to the lower position L, whereupon the above described process is repeated. The piston of the air cylinder 6 is therefore moved reciprocally, and the drum 3 is rotated, and transfers fasteners 38 from the hopper 2 onto the chute 16, as described earlier.  
  Air which has passed through the relay R1 is supplied to a main line P1, and to a line P2. The regulator R1 is spring-loaded to normally permit passage of air therethrough to the lines P1 and P2. A portion of the air passing through the regulator R1 is supplied to a feedback line R1, and acts to oppose the force of the spring holding the regulator R1 open, whereby at certain pressures of air passing through R1, the force of the air supplied along the feedback line R1 is sufficient to move the regulator R1 to a closed position, and the regulator R1 is not returned to an open position until the pressure of the air supplied along the feedback line R1 drops to a certain value.  
  Air supplied along the main line P1 passes through a switch S1, and a restriction orifice to the channel 30 of the detection blower 20. A line P11 leading from the line P1, and containing a restrictionorifice, supplies air to the signal emitters 28 and 29. The line P2 leads to a normally closed switch valve B2, which connects to the distributor 18. The distributor 18 is also connected by a feedback line to the line P2, in order to establish. requisite air pressures to feed the fastener 38 in the distributor 18.  
  Output from the emitter 28, which is higher on the chute 16, is supplied through a line P to two lines P101 and P102. The line P101 leads to a control port 78A of the NOR element 78. The line P102 connects to an input of a delay valve DV1. The output of the delay valve DV1 connects to a control port 80B of the above-mentioned bistable element 80. The delay valve DV1 is also connected through a line P103, containing a restriction orifice, to the main supply line P1.  
  Output from the lower signal e&#39;initter 29 is supplied along a line P9 to the other control port 78B of the NOR element 78. The NOR element 78 has an output port 78F, at which output is produced&#39;only when input to both the control ports 78A and 78B&#39;is zero or none. The NOR element output port 78F connects to the other control port 80A of the&#39;bistable element 80.  
 Input to the bistable element from the NOR element 78 causes output from the bistable element 80 to be produced at the output port 80F2. Input from the delay valve DV1 causes the bistable element 80 output to be produced at the other outlet port 80F1. Upstream supply to the elements 78 and 80 is supplied along lines all and a12, which lead from a line a1 connecting to a line a. The line a connects through a restriction orifice to the main line P1.  
  A line P4 containing a restriction orifice provides a connection between the main line P1 and the air inlet 60 of the fastening device signal emitter 52. The outlet 61 of the emitter 52 is connected to the abovementioned monostable element 79, which functions as a one-shot multivibrator, by a line P5. Output from the monostable element 79 is supplied as input to a control port 81B of a bistable element 81. This input causes the bistable element to produce output at an output port 81F1, which connects to a line P7 leading to the normally closed switch valve B2. When output is supplied from the bistable element output port 81Fl, along the line P7, the switch valve B2 is moved against the force of a spring holding it closed, to a position in which the valve B2 provides communication between the distributor 18 and the supply line P2, whereby the distributor 18 is actuated to supply a fastener 38 to the fastening device 51, as described above. Input to the other control port 81A of the bistable element 81 is supplied from a timer TM.  
  The timer TM also connects to the line P7, both directly and through a gage valve TMl. The timer TM is further connected to the main line P1 through a line Tl containing a restriction orifice. Input from the timer TM to the bistable element 81 causes output from the element 81 to be produced at the other output port 81F2 thereof, whereby air supply along the line P7 to the switch valve B2 is cut, the valve B2 is returned by a spring force to a closed position, air supply along the line P2 to the distributor 18 is cut, and operation of the distributor 18 ceases. Upstream supply to both the elements 79 and 81 is supplied along lines a2l and 022, which lead from a line a2 connecting to the abovementioned line a.  
  The description will now proceed in reference to the operation of the first control circuit which maintains a supply of fasteners 38 to the distributor 18.  
  To start operation the switch S1 is switched to permit air coming from the air compressor AC, and through the filter F1 and regulator R1, to flow into the main line P1, whereby air is supplied to the detection blower 20 and the upper and lower signal emitters 28 and 29. Presuming now there are no fasteners on the chute 16, the air jets across both the gaps 33a and 33b of the signal emitters 28 and 29 are interrupted by air projected downwards from the nozzles 32a and 32b, respectively (see also FIGS. 5(a), 5(1)) and 6). There is therefore no output from the emitter 28 along the line P10, or from the emitter 29 along the line P9, and accordingly no input along the line P102 to the delay valve DV1, or along the lines P101 and P9 to the control ports 78A and 78B of the NOR element 78. There being no input at either control port 78A and 78B, an output from the NOR element output port 78F is supplied as input to the control port 80A of the bistable element 80, thereby switching output from the element 80 to the output port 80F2. This output is supplied along the line P8 to open the switch valve Bl, whereby air coming from the oiler 01 and along the line P6 is supplied to the oscillator 82, the air cylinder 6 is actuated, and fasteners 38 are supplied onto the chute 16 by the drum 3. The supply of fasteners 38 onto the chute 16 is generally faster than the use thereof by the fastening device 51, and the supply of fasteners 38. ready for distribution, on the chute 16 steadily builds up. When the number of fasteners 38 on the chute 16 is such that a fastener 38 is held between the detection blower nozzle 32b and the lower signal emitter 29, the signal emitter 29 produces an output along the line P9 to the control port 78B of the NOR element 78, while output of the upper signal emitter 28 continues to be zero. Conditions along the lines P10, P101 and P102 therefore continue unchanged, but output at the NOR element output port 78F, ceases, and there is no input to the control port 80A of the bistable element 80. However, there is no switching input to the control port 80B either, and so output of the bistable element 80 continues to be produced at the output port 80F2, and the drum 3 continues to be actuated to supply fasteners 38, from the hopper 2, onto the chute 16. When the fasteners 38 on the chute 16 reach the level of the upper signal emitter 28, air from the nozzle 32a can no longer interrupt the jet across the gap 330 of the emitter 28, and so the emitter 28 produces an output which is transmitted along the lines P10, P101 and P102. The input along the line P101 to the NOR element control port 78A does not change the state of the NOR element 78, since there is already an input at the port 78B. The output signal transmitted along the line P102 is supplied to the delay valve DVl. After about 0.5 seconds the delay valve DVl produces an output which is supplied as input to the control port 80B of the bistable element 80, and switches the output of the element 80 to the port 80 Fl thereof. Air supply along the line P8 is therefore cut, and the switch valve B1 is returned by spring force to a closed position, thus cutting supply to the oscillator 82 from the line P6, whereby action of the air cylinder 6 and rotation of the drum 3 cease, and fasteners 38 are no longer supplied to the chute 16. As fasteners 38 are distributed by the distributors 18 to the fastening device 51, for use thereby, the number of fasteners 38 on the chute 16 decreases. When the highest fastener on the chute 16 moves to below the level of the lower signal emitter 29, the abovedescribed process is repeated.  
  In reference now to the second control circuit, which effects transfer of fasteners 38 from the distributor 18 to the fastening device 51 (FIG. 8), presuming that there is no fastener 38 in the fastening device 51, the second control circuit is actuated by causing the slide shaft 55 of the fastening device 51 to slide into the main unit 54 thereof, that is, by actuating the fastening device 51 as though there were a fastener 38 therein. This cuts communication between the air inlet 60 connected through the line P4 to the main line P1, and outlet 61 connecting to the line P FIGS. 9(a) and 9(b). Air pressure builds up at the inlet 60, and when the slide shaft 55 is allowed to move out of the main unit 54, and communication is established between the inlet 60 and outout 61 FIGS. 10(a) and (10b), a trigger signal is supplied along the line P5 to the input port 79A of the monostable element 79. The monostable element 79 thereupon produces an output, which is supplied as input to the control port 81B of the bistable element 81, and causes output of the bistable element 81 to appear at the output port 81F1 thereof. Output from the monostable element 79 ceases rapidly, because the flow of air thereto becomes steady, and because of the impedance of the line P5, but the bistable element 81 remains switched to produce output at the port 81F1, until receipt of an input at the control port 81A, as described below.  
  Output from the bistable element 81 is supplied along the line P7 to open the switch valve B2, and also to the timer TM. When the valve B1 is opened air is supplied to the distributor 18 through the line P2, and a fastener 38 is supplied to the fastening device 51, as described above. While the distributor 18 is thus in operation, air is being supplied to the timer TM, and after a set time, the timer TM supplies a switching input, along the line T2, to the control port 81A of the bistable element 81. Output from the bistable element 81 is therefore switched to the output port 81F2, supply along the line P7 is cut, and the switch valve B1 is returned by spring force to a closed position, whereby supply along the line P2 to the distributor 18, and operation of the distributor 18 ceases. In other words, the duration of the functioning of the distributor 18 is determined by the setting of the timer TM. When the fastening device 51 is actuated to attach the fastener 38 supplied thereto to some object, the abovedescribed process is repeated.  
  The description of the invention now proceeds in reference to a second embodiment thereof, which is shown in FIGS. 12 through 18.  
  Referring now to FIGS. 12, 13 there is shown a fastener feed assembly which functions in a generally similar manner to that of the feed assembly shown in FIGS. 1, 2, and may be suitably controlled by a drive control means according to the second embodiment. The fastener feed assembly shown in FIGS. 12 and 13 comprises a hopper 85 supported on a frame 84, and a drum 86 which is provided with scoops 87 and, when rotated, transfers fasteners 38 from the hopper 85 to a guide tray 102 which guides fasteners 38 into a chute 101. The chute 101 comprises two parallel boards 101a, 101b, which are downwardly inclined and extend from a point generally above the hopper 85 to a distributor 103, which is located below the level of, and forward of the hopper 85. The portions of the boards 101a and 10lb which are outside the hopper 85 are supported on support arms 106. The forward portion of chute 101 is also provided with boards 105, which are for the purpose of maintaining suitable separation between fasteners 38 sliding down the chute 101. Just before the exit of the chute 101 from the hopper 85 there is provided a rejector wheel 104, which returns incorrectly aligned fasteners 38 to the hopper 85. The drum 86 is rotatably mounted on a shaft 89, which is supported by a frame 88. The frame 88 is supported by a vertical plate 100, which is fixedly attached to the frame 84. A bracket 99 extending generally at rightangles from the plate 100 provides support for a vertically aligned cylinder rod 96, the lower end of which is fixedly attached to the upper end of the piston of a vertically aligned air cylinder 90, whereby actuation of the air cylinder 90 causes the cylinder rod 90 to move reciprocally upwards and downwards. The drum 86 is driven by rotation of a ratchet wheel 91, which is fixed thereto, and mounted coaxially therewith on the shaft 89. The ratchet wheel 91 is rotated by pawls 92a, 92b provided respectively at ends of linkage arms 93a, 93b, the other ends of which are rotatably mounted on the shaft 89. Ends of linkage arms 94a, 94b are in rotatable attachment to the linkage arms 93a, 93b, respectively. The other ends of the linkage arms 94a, 94b are in rotatable attachment to a block 95, which is fixedly mounted on the upper end of the cylinder rod 96, whereby actuation of the air cylinder 90 causes rotation of the drum 86, in the same manner as described in reference to the feed apparatus of the first embodiment.  
  In the second embodiment, there is not provided an oscillator unit 13, but control of the air cylinder 90 is effected through a reciprocator valve 98 and a switching element 97. The reciprocator valve 98 is supported at a point on the plate 100 near to the cylinder rod 96, and comprises a flap 98a, which extends towards the cylinder rod 96. The switching element 97 is fixedly mounted on, and moves reciprocally upwards and downwards together with the cylinder rod 96, and comprise an upper switching extension 97a and a lower switching extension 97b. The valve flap 98a is pushed by the lower extension 97b or pulled by the upper extension 97a, according to whether the cylinder rod 96 reaches a topmost or lowermost position, whereby the recipricator valve 98 is actuated to control air flow to the air cylinder 90, as described in further detail below. Also, in the second embodiment the control box 22 is replaced by a control section CS located below the hopper 85, and comprising throttle valves 150 and 155, switch valves 149 and 153, changeover valves 146 and 151, and starting button 156a, which are described in further detail below.  
  Referring to FIGS. 14 and 15 the lower end of the chute 101 is connected to the distributor 103 by connector boards 108. The distributor 103 functions in the same manner as the fastener distributor described in reference to the first embodiment, and comprises a main housing 109, a fixed block 116, which is fixedly attached to the main housing 109 and in which there is formed a fastener guide passage 107 communicating with a connection piece 117, and a slide block 112 which is slideable between the fixed block 116 and main housing 109 and comprises a cut-out portion 112a, wherein fasteners 38 may be carried from the bottom of the chute 101 to the guide passage 107. A spring-loaded plunger 111 is slidably mounted in a cylinder 110, which is formed in the main housing 109, and at opposite ends of which there are provided cylinder heads 114, 115. One end of the plunger 111 is exterior to the main housing 109, and is connected to one end of the slide block 1 12 by a fixedly attached connection plate 113, whereby actuation of the plunger 111 also actuates the slide block 112. Air supplied to it in a manner described below actuates the distributor 103 to transfer a fastener 38 from the chute 101 to the guide passage 107. Fasteners 38 thus transferred are moved by air pressure to the connection piece 117, through a distribution pipe 118 connected thereto, and to the feed-in pipe 123 of a fastening device 119.  
 In FIG. 16, the fastening device 119 may be seen to comprise a forward portion 124, a pneumatically driven screwdriver 125, or similar means, a slide shaft 124a, a main unit 120, and a handle 126. The slide shaft 124a slides into the main unit 120 when the fastening device 119 is in use and is heldforwardly extended, relative to the main unit 120, by a spring 127, during non-use of the fastening device 1 19. A dog 128 is attached to a rear portion of the slide shaft 124a.  
 When the fastening device 119 is being used to attach a fastener-38 to some object, and the slide shaft 124a is slid into the main unit 120, the dog 128 actuates a signal emitter 121, which is fixedly attached to the main unit 120 by screws 122a 122b.  
  Referring now to FIG. 17, the signal emitter 121 may be seen to comprise a main block in which there are formed valve chambers 139a and 139b, connecting channel 136a, and outlet channel 136b. The longitudinal axes of the valve chambers 139a and 139k are generally parallel to the front-to-rear, longitudinal axis of the signal emitter 121, and the chambers 139a and 13% are formed in line with one another, chamber 139a being forward of chamber 13%, with respect to the signal emitter 121.  
  The rear end of the valve chamber 13% opens at the rear surface of the main block 130 and forms an inlet 131, into which a connector 134 is securely inserted. An inlet tube 133 is fitted on the connector 134. The tube 133 brings air supplied along a line Lla (described below) to the signal emitter 122. The forward end of the chamber 13% is narrowed and communicates with a small diameter passage 135, which also communicates with the rear end of the other valve chamber 139a. The passage is normally sealed by a ball 143 which is normally urged to the forward end of the chamber 13% by an expansion spring 142 provided within the chamber 139]).  
  Still referring to FIG. 17, the forward valve chamber 139a extends from the passage 135 to the front of the main block 130. A slide rod 129 is slidably mounted in the chamber 139a. The forward portion of the slide rod 129 constitutes a large diameter portion fitting slidably into, and through, a stop screw 141 which is mounted in the front end of the chamber 139a. The rear portion 12% of the slide rod 129 forms a narrow diameter portion which may pass through the passage 135 and extend into the rear valve chamber 13%. An expansion spring provided in the chamber 139a and mounted around the slide rod 129 exerts a constant force urging the slide rod 129 towards the front end of the chamber 139a, and into a position in which the forward end 129a of the slide rod 129 projects forwards, beyond the front surface of the main block 130. When the slide rod 129 is in this configuration, the rear portion 12917 thereof does not extend into the passage 135. When the fastening device 119 is actuated and the slide shaft 124a thereof is slid into the main unit 120, the dog 128 attached to the slide shaft 124a contacts the forward end 129a of the signal emitter slide rod 129, and pushes the slide rod 129 rearwards into the chamber 139a, against the force of the spring 140. When the slide rod 129 is thus moved rearwards, the rear portion 12% thereof passes into and through the passage 135, and pushes the ball 143 rearwards, whereby air entering the inlet 131 may pass through the chamber 139b, through the passage 135, and into the chamber 139a.  
  The abovementioned connecting channel 136a communicates with and is formed generally at right-angles to the chamber 139a. The outlet channel l36b is a continuation of the connecting channel 136a, formed generally at right-angles thereto, extending generally parallel to the rear valve chamber 139b, and forming an outlet 132 at the rear surface of the main block 130. A connector 137 is securely inserted in the outlet 132, and is connectedto a tube 138, which supplies air to a line L4 (described below). When the slide rod 129 is pressed rearwards by the dog 128, air entering through the inlet 131 may therefore pass through the chamber 13% and passage 135, into the chamber 139a, and from the chamber 139 into and through the channels 136a and 136b to the outlet 132. In other words unlike the distribution signal emitter of the first embodiment, the signal emitter 121 of the second embodiment produces a signal output when the fastening device 119 is in use.  
  Reference is now had to FIG. 18, which is a schematic circuit diagram of fluid paths in the drive control means according to the second embodiment of the invention.  
  Air is supplied to the circuit from an air compressor AC, or other suitable means. Air coming from the air compressor AC first passes through a filter 144, and then divides into two paths constituted by lines L1 and L2. Air following the line Ll passes through an oiler 145, which provides oil for lubrication of various mechanical parts. The line L1 leads to two lines Lla and Llb which connect respectively to the fastening device 1 19 and the inlet tube 133 of the fastening device signal emitter 121, as indicated in the upper left-hand portion of FIG. 18.  
  Branch lines L11, L12 and L13 lead off from the line Ll (lower right-hand portion of FIG. 18). The line L11 is connected to a switch valve 153 which is springloaded in a normally closed position. When the valve 153 is opened, in a manner described below, the valve 153 connects the line L11 to a line L14. The line L14 leads through a valve 156 to a line L15. The valve 156 has two positions which are position I, in which the valve connects the line L14 to the line L15, and position II, in which the valve 156 connects the branch line L12 to the line L15. The valve 156 is spring-loaded to be normally in position I, and may be moved to position II by depression of the abovementioned start button 156a provided on the control section CS below the hopper 85. The line L15 leads to the above-mentioned reciprocator valve 98 which is provided on the support bracket 100 and is actuated by the switch element 97 mounted on the cylinder rod 96 (FIG. 12). Action of the valve 98 will be described further below.  
  Still referring to FIG. 18, the line L13 supplies air to an oscillator 154 which drives the air cylinder 90. The oscillator 154 has two positions, which are position U and position L. When in position U, the oscillator 154 connects the line L13 and a lower pipe 90b leading to the air cylinder 90. In this case, air is supplied into the air cylinder 90, causes the piston thereof to rise, and exits through an upper pipe 90a. When in position L, the oscillator 154 connects the input line L13 to the upper pipe 90a of the cylinder 90, whereby air entering the cylinder 90 causes the piston thereof to move downwards, and exits through the lower pipe 90b. The oscillator 154 is spring-loaded to be normally in the position U, and may be moved to position L by the pressure of air supplied along a line L16 which connects to the reciprocator valve 98.  
  The reciprocator valve 98 has two positions, in which it is open or closed, respectively. When the piston of the air cylinder 90 reaches a lowermost position the switch extension 97a of the switch element 97 pulls the valve flap 98a, and closes the valve 98. In this situation, air coming along the line L15 cannot pass through the valve 98, and therefore no air issupplied along the line L16; the oscillator 154 is in the position U, and air supplied along the input line L13 enters the lower pipe b and causes the piston of the air cylinder 90 to rise. When the piston reaches a topmost position, the switch extension 97b pushes the valve flap 98a and opens the valve 98. The valve 98 now connects the lines L15 and L16, and the pressure of air supplied along the line L16 pushes the oscillator into position L, and the piston of the air cylinder 90 is moved downards. The above described action is repeated for as long as air is supplied along the line L15. As noted earlier, air is su&#39;pplied along the line L15 only when the valve 153 is open to connect the lines L11 and L14, or when the starter button is depressed to connect the lines L12 and L15.  
  Air entering the line L2 first passes through a regulator 147, which, similarly to the regulator R1 of the first embodiment, is provided with a feedback line to ensure that pressure along the line L2 does not exceed a certain value. The line L2 supplies air to lines L21, L22 and L23, which are respectively connected to a changeover valve 151, a switch valve 149, and a changeover valve 146.  
  The changeover valve 146 is connected to a line L24 leading to an air tank 148, and has two positions, 146A and 146B. The valve 146 is spring-loaded to be normally in position 146A, and in this position provides communication between the line L24 and a line L41, which leads to the switch valve 149, and which also is connected to a line L42 leading to a vent 150. Flow of air through the vent is controlled by a throttle valve 150a. The valve 146 may be moved against the spring-loading force, to position 146B by pressure of air supplied along the abovementioned line L4, which connected to the outlet tube 138 of the fastening device signal emitter 121. The line L4 also supplies air to a line L5, which leads to the changeover valve 151. When the valve 146 is in position 146B, it connects the lines L23 and L24, and disconnects the lines L24 and L41.  
  The switch valve 149 is spring-loaded to be normally closed, but may be pushed into an open position by pressure of air supplied along the line L41. When open, the valve 149 provides connection between the line L22 and a line L25. The line L25 leads to and supplies air to actuate the distributor 103 to supply a fastener 38 to the fastening device 119.  
  The changeover valve 151 connected to a line L26 leading to an air tank 152, and has two positions, 151A and 151B. The valve 151 is spring-loaded to be nor mally in position 151A, and in this position the valve 151 connects the line L26 to a line L51, which leads to the abovementioned switch valve 153, and which is also connected to a line L52 leading to a vent 155. Flow of air through the vent is controlled by a throttle valve 155a. Air supplied along the line L51 pushes the switch valve 153 open, in which case the valve 153 connects the lines L11 and L14, as described above. The changeover valve 151 may be pushed to position 151B by pressure applied thereto by air flowing along the line L5. In position 151B, the valve 151 connects the lines L21 and L26, and disconnects the lines L26 and L51.  
  The description will now proceed first in reference to the action of the above described circuit in causing fasteners 38 to be supplied from the distributor 103 to the fastening device 119, and then in reference to the action of the circuit in causing the drum 86 to supply fasteners 38 from the hopper 85 to the chute 101. These