Swing arm type clamp feeder

Abstract

To stabilize a function of determining whether a clamped sheet is increased or decreased for a long period of time in a swing arm type clamp feeder which clamps and feeds a bottom sheet of a stack of sheets.SOLUTION: A lower clamp is provided at a lower end of a linear motion rod that is made linearly movable by a slide bush fixed to a swing arm, an upper clamp is provided at a lower end of the swing arm, and a distance sensor is further provided on the swing arm and a sensor dog facing the distance sensor is provided on the linear motion rod, in which a thickness of a sheet clamped between the lower and upper clamps is measured and checked.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a swing-arm clamp feeder that frequently feeds sheets from a stack of paper, starting from the bottom, such as postcards, various cards, flyers, catalogs, booklets, slips, envelopes, etc. It also relates to improvements to collators, inserters, and machines that incorporate multiple such feeders. [Background technology]

[0002] In the industry, the main feeders can be broadly divided into clamp-type feeders, which clamp and pull out the bottom sheet of a stack of paper with a pair of mechanical clamps, and friction-type feeders, which use the friction of rubber rollers or rubber belts to feed paper. The feeder in this application belongs to the former type, and particularly relates to a swing-arm clamp feeder, which repeats forward and back movements of a swing arm around a swing fulcrum, closes the clamp to clamp the paper when the arm switches from forward to back movement, checks the paper thickness during the back movement, and opens the clamp just before switching to forward movement, releasing the pulled-out paper to feed paper. For example, the following is known as similar prior art. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-72324 [Patent Document 2] Japanese Patent Application Publication No. 8-67401 Summary of the Invention [Problem to be solved by the invention]

[0004] A drawback of the feeders based on the above-mentioned prior art is the difficulty of maintaining stable measurement of the clamped paper thickness during double-action operation. This is due to a structural problem. Given the routine operation of the feeders, which operate tens of thousands of times per day, wear and looseness in various mechanical components is inevitable, resulting in problems with paper thickness measurement. For example, while copy paper is about 50 to 70 microns thick, fliers and forms are often made of thin paper, about 30 to 50 microns thick.

[0005] The purpose of measuring paper thickness with this type of feeder is to check for missing pages if the paper fails to be clamped due to poor adjustment, or to check for missing pages if two copies are clamped when only one copy should be. In practice, relatively stable results can be obtained for paper that is thicker than the aforementioned copy paper, but for thinner paper, the judgment results tend to malfunction more often, and the older the feeder, the more frequent the malfunctions. In essence, there is a problem with the mechanism, and the structure is such that wear and play in the mechanical parts negatively affects the measurement results.

[0006] Specifically, in conventional feeders, the mechanism from the clamp to the thickness measurement point includes a fulcrum mechanism for opening and closing the clamp. Because this fulcrum rotates extremely frequently, it is maintained (oiled) to prevent wear. What is important to understand here is the fit between the fulcrum shaft and the bearing. Generally speaking, if the shaft can be easily inserted into the bearing by hand, there should be a dimensional difference of about 20 to 30 microns in diameter (the shaft is thinner), and this amount of play is already present in the early stages. If this wear progresses, the measurement results will become unstable. In other words, the degree of wear and play in the fulcrum mechanism has a significant negative impact on paper thickness to a level that cannot be ignored.

[0007] In practice, a teaching method is used in which one sheet of paper is clamped even when there is play, and the measurement value is used as the reference value. However, this does not provide a fundamental solution, and re-teaching is required every time a malfunction occurs. Furthermore, when the paper becomes thin, this cannot be handled, and the collator or inserter is operated with the sheet increase / decrease function turned off. The present invention provides a swing-arm type clamp feeder that is configured with a novel mechanism that does not adversely affect paper thickness measurement even when wear and rattle occurs in mechanical parts. [Means for solving the problem]

[0008] The present invention provides a swing arm type clamp feeder characterized in that it is provided with a lower clamp at the lower end of a linear motion rod, which is inserted into and supported by a slide bush fixed to a swing arm, and an upper clamp at the lower end of the swing arm that forms a pair with the lower clamp to clamp the edge of the paper, and further provided with a distance sensor on the swing arm and a sensor dog on the linear motion rod that faces the sensor, and is configured so that the clamp is closed to clamp the paper just before the swing arm switches from forward movement to backward movement, the paper thickness is checked during the double movement, and the lower clamp is opened just before switching to forward movement to release the pulled out paper, thereby feeding paper.

[0009] The present invention also provides a swing arm type clamp feeder characterized in that it is provided with a lower clamp at the lower end of a linear motion rod, which is inserted into and supported by a slide bush fixed to a swing arm, a cam floor at the upper end, which engages with the cam peripheral surface fixed to a cam shaft that is the swing arm's swing fulcrum, and an upper clamp at the lower end of the swing arm that forms a pair with the lower clamp and clamps the edge of the paper, and further provided with a distance sensor on the swing arm and a sensor dog on the linear motion rod that faces the sensor, and is configured so that the clamp is closed to clamp the paper just before the swing arm switches from forward to backward motion, the paper thickness is checked during the double motion, and the lower clamp is opened just before switching to forward motion to release the pulled out paper, thereby feeding paper. [Effects of the Invention]

[0010] Because the feeder of the present application is designed to open and close the clamp with the linear reciprocating motion of the linear motion rod, even if wear and rattle occurs in the linear motion rod, the thickness dimension held by the clamp can be directly reflected in the sensor and dog without going through a fulcrum mechanism, etc. As a result, errors caused by wear and rattle are not generated, and extremely stable measurement performance (function to check for added or missing pages) is demonstrated over the long term. Furthermore, in the case of a feeder configured with a cam floor at the upper end of the linear motion rod, the mechanical structure is significantly simpler than that of conventional feeders, making it possible to provide the relevant industry with a small, low-cost feeder. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a side view of the feeder of the present invention. [Figure 2] An explanatory diagram illustrating the main components of the feeder of the present invention. [Figure 3] An explanatory diagram illustrating the main components of the feeder of the present invention. [Figure 4] An explanatory diagram illustrating the side view of a typical feeder configured with a conventional mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention is implemented as a stable, low-cost, novel feeder device in processes that feed large quantities of various types of paper one by one at high speed, such as bookbinding, collating, and enclosing and sealing processes. [Example]

[0013] The feeder according to the present invention will be described below with reference to FIGS. Figure 1 is an explanatory diagram of the case where a feeder according to the present invention is installed in the collating section of a collating machine or inserter. In the figure, 25 denotes a chain, and 21 denotes fingers provided at predetermined intervals, each of which forms a finger pocket, and conveys collated material 23 from right to left on the paper surface. The feeder according to the present invention is installed above the finger conveyor, and clamped sheets 37a are released and fed into the finger pockets that arrive one after another.

[0014] That is, a known suction pad 20 acts on the bottom sheet of a stack of paper 37 placed on the paper loading table 21 along the front ruler 22, bending it downward as shown in the figure, and a pair of clamps 1 and 2 (described later) enter as the swing arm 10 moves forward (swings from right to left on the paper), clamps the edge of the paper, and then pulls it out as the swing arm 10 moves double (swings from left to right on the paper), and as shown in the partial explanatory diagram on the right side of the figure, the clamps are released just before switching from double action to forward action.

[0015] Figures 2 and 3 are explanatory diagrams for explaining the configuration of the feeder of the present invention in more detail. Note that Figure 3 is an explanatory diagram of the device in Figure 2 as viewed from the right side, and a partial explanatory diagram is added to the right side of the figure to clearly show the engagement relationship between the cam 8 and the cam floor 7.

[0016] 1 to 3, reference numeral 10 denotes a swing arm whose fulcrum is formed on camshaft 9 via a bearing (not shown), and which repeats swinging motion by means of a crank or the like (not shown) in conjunction with the timing of the arrival of finger 24. An upper clamp 2 is attached to the lower end of swing arm 10, and a slide bush 4 and a thickness measurement sensor 5 are also attached thereto.

[0017] A linear actuator shaft 3 is inserted through the slide bush 4, and a lower clamp 1 is fixed to the lower end of the linear actuator shaft 3. That is, the lower clamp 1 forms a pair with the upper clamp 2, and opens and closes the linear actuator rod 3 to clamp the edge of the paper 37a. When a cam 8 fixed to a cam shaft indicated by 9 rotates, a cam floor 7 provided at the upper end of the linear actuator rod 3 moves along the cam circumferential surface, resulting in the linear actuator rod 3 controlling the opening and closing of the lower clamp 1 at a predetermined timing. The linear actuator rod 3 is constantly biased upward by a spring 11, and this force provides a clamping force sufficient to pull the bottom paper from the stack of paper 37. While the paper 37a is being clamped, the cam floor is slightly spaced from the circumferential surface of the cam 8.

[0018] Now, what is noteworthy here is the configuration of the sensor 5 and sensor dog 6, which are configured to measure the thickness of the paper 37a clamped between the pair of clamps 1 and 2. The sensor 5 is fixed to the swing arm 10, and the L-shaped sensor dog is fixed at a predetermined position on the linear motion rod. In this embodiment, an analog output proximity sensor is used as an example, and the sensor 5 outputs an output related to the distance from the sensor dog 6 to obtain thickness information for the paper 37a. In other words, the thickness information for the paper 37a is obtained by measuring the position of the linear motion rod 3. Therefore, any sensor having such a function can be selected and used from within the known technical scope. For example, a laser distance sensor or what is called a magnescale can also be used. In either case, a sensor that detects position and a sensor that is detected are installed as a pair, and one of them can be installed on the swing arm 10 and the other on the linear motion rod 3.

[0019] The feeders of the present invention are characterized in that the position information of the lower finger 1 attached to the lower end of the linear motion rod 3 is directly reflected in the sensor output value without any mechanism. In contrast, in the typical configuration of the conventional device shown in Figure 4, the lower finger 1 is attached to a lower arm 34, which is supported by a fulcrum 33 attached to the lower end of the swing arm 10 and connected to a cam mechanism 31 via a connecting rod 32. As shown in the figure, the sensor 5 and sensor dog 6 are attached in the same manner as in the feeder of the present invention. However, a major difference is that a fulcrum 33 is interposed between the lower finger 1 and the sensor dog 6.

[0020] Wear and play develops at this fulcrum 33. The reality of operation in this field is that tens of thousands of times a day are commonplace, which gradually makes it impossible to accurately measure paper thickness. Malfunctions of the sheet sensor occur frequently, especially when paper thinner than copy paper is used. For inserters used in the manufacture of standard-sized mail items subject to weight restrictions, the thickness of the paper used is becoming increasingly thinner in order to reduce the weight of the items to be inserted. Therefore, the demand for improvements in this type of inserting and sealing process is growing stronger every day.

[0021] In contrast, the feeder of the present application does not have such a fulcrum structure, and malfunctions in the added / missing sheet detection due to aging rarely occur. As is clear from the explanatory diagram of the illustrated embodiment, wear play can occur between the slide bush 4 and the linear motion rod 3. Even if there is a play of 50 microns, it is in the direction perpendicular to the thickness measurement direction and cannot become a cause of instability in the thickness direction. In other words, the reliability of the added / missing sheet detection of the feeder of the present application remains extremely stable over a long period of time.

[0022] Regarding the slide bush 4 and linear motion rod 3, the latter is inserted into the former to hold it so that it can reciprocate in the direction of its extension, and components called linear bushings and linear shafts can be used. Generally, the linear motion rod is a round bar with a circular cross section or a rod with a polygonal cross section, and its outer surface is supported by a number of balls so that it can slide only in the direction mentioned above. Alternatively, if necessary, both can be configured using components called linear guides.

[0023] Next, regarding the cam 8 that moves the linear motion rod 3 to open and close the clamp 1, the unique configuration of the present application in which the cam 8 is provided on the cam shaft 9 that serves as the swing fulcrum of the swing arm 10 and is engaged with the cam floor 7 provided at the upper end of the linear motion rod 3 contributes to making the overall size of the device extremely small. In other words, by configuring the mechanism simply through the cam floor 7, not only is the device more compact, but the manufacturing costs are also certainly reduced. [Industrial Applicability]

[0024] As described above, the swing arm clamp feeder of the present invention, as well as the collating machine, inserting machine, standard inserter, or non-standard inserter that incorporates the feeder, enable stable long-term operation of the added / missing page check, even when the paper being fed is extremely thin, and solves the malfunction problem that has been an issue with conventional feeders, making a significant contribution to the relevant industries. Furthermore, compared to conventional feeders, the cam mechanism proposed in this application has a simpler configuration, making it possible to provide the relevant industry with a small, low-cost, long-life feeder. [Explanation of symbols]

[0025] 1 Lower clamp, 2 Upper clamp, 3 Linear rod, 4 Slide, 5 Sensor, 6 Sensor dog, 7 Cam floor, 8 Cam, 9 Cam shaft, 10 Swing arm, 11 Tension spring, 20 Suction pad, 21 Paper tray, 22 Front ruler, 23 Collated material, 24 Finger, 25 Chain, 31 Cam mechanism, 32 Connecting rod, 33 Fulcrum, 34 Lower arm, 37 Paper stack, 37a Pulled out paper

Claims

1. A swing arm type clamp feeder characterized in that it is provided with a lower clamp at the lower end of a linear motion rod, which is inserted into and supported by a slide bush fixed to a swing arm, an upper clamp at the lower end of the swing arm which forms a pair with the lower clamp to clamp the edge of the paper, a distance sensor is further provided on the swing arm and a sensor dog facing the sensor is provided on the linear motion rod, the clamp is closed to clamp the paper just before the swing arm switches from forward to backward motion, the paper thickness is checked during the double motion operation, and the lower clamp is opened just before switching to forward motion to release the pulled out paper, thereby feeding the paper.

2. a cam floor at the upper end of the swing arm, the cam floor engaging with the cam circumferential surface fixed to the cam shaft which is the swing arm's pivot point; an upper clamp at the lower end of the swing arm which pairs with the lower clamp to clamp the edge of the paper; a distance sensor on the swing arm and a sensor dog on the linear motion rod facing the sensor; a clamp closing to clamp the paper just before the swing arm switches from forward to backward movement, checking the paper thickness during the double movement; and opening the lower clamp just before switching to forward movement to release the pulled-out paper, thereby feeding paper.

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