Concrete Pump

Abstract

To simultaneously solve a first problem when an elastic pad is formed of a high-hardness elastic material and a second problem when the elastic pad is formed of a low-hardness elastic material by a simple structure, in a concrete pump which has a pair of rollers rolling while pressing an intermediate part of a tube and exerting a pump action and the elastic pad arranged at an internal peripheral face of a pump case external peripheral wall and capable of gripping the tube between itself and the roller, wherein the other roller starts pressing almost simultaneously with when one roller releases the pressing, accompanied by the revolution of the pair of rollers.SOLUTION: An elastic pad P which is arranged at an internal peripheral face of a pump case external peripheral wall CA, and can grip a tube T between itself and a roller R is dividedly constituted of at least two pieces of partial pads Pb, Pt, Pf1 and Pf2 including the upper pad Pt which is nearest to a discharge port Co of a pump case C, and the lower pad Pb which is nearest to a suction port Ci of the pump case, and the upper pad Pt is constituted of an elastic material whose hardness is lower than that of the lower pad Pb.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a concrete pump, and in particular to a concrete pump comprising a pump case formed approximately cylindrically with a suction port at the bottom of the rear half of the outer peripheral wall and a discharge port at the top, a tube whose middle portion extends in an arc shape so as to follow the inner peripheral surface of the front half of the outer peripheral wall of the pump case, with one end extending in an approximately tangential direction to the outer peripheral wall through the suction port and the other end extending in an approximately tangential direction to the outer peripheral wall through the discharge port, a pair of rollers which roll while pressing against the middle portion of the tube to cause the tube to exert a pumping action, and elastic pads which are provided along the inner peripheral surface of the outer peripheral wall and can clamp the tube between them, the pair of rollers being configured to revolve around the central axis of the pump case with a phase difference of 180 degrees, and so that as the rollers revolve, approximately at the same time that one roller releases the pressure, the other roller begins to press.

[0002] In the present invention and this specification, the front side and rear side refer to the side where the suction port and discharge port are located as viewed from the center of the pump case, which corresponds to the rear side, and the opposite side corresponds to the front side. Also, when the concrete pump is mounted on a vehicle, the front-to-rear direction of the vehicle coincides with the front-to-rear direction, and the up-down direction of the vehicle coincides with the up-down direction. [Background technology]

[0003] The above-mentioned concrete pump is conventionally known, for example as disclosed in Patent Document 1, and can be used to pump ready mixed concrete to, for example, a high-altitude construction site. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-41179 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the concrete pump of Patent Document 1 mentioned above, the elastic pad installed along the inner surface of the front half of the outer wall of the pump case is made of a continuous, one-piece elastic material (and therefore of the same hardness) from the suction port at the bottom of the case to the discharge port at the top of the case, which has the following disadvantages:

[0006] That is, the roller in the discharge process (hereinafter referred to as the discharge side roller in this specification) rolls while strongly pinching the tube it presses against between itself and the elastic pad, thereby enabling the fresh concrete to be pumped downstream of the tube while suppressing backflow. Therefore, if the upper pad portion of the elastic pad has a low hardness, there is a first problem in that the backflow of fresh concrete cannot be effectively suppressed just before the discharge side roller releases its pressure on the tube (i.e., the latter half of the discharge process when the pumping load from the fresh concrete being pumped to high places increases), causing a decrease in pump efficiency.

[0007] On the other hand, there is a second problem in that when the next roller (hereinafter referred to as the suction side roller in this specification) begins to press against the tube and begins to clamp the tube between it and the lower pad portion of the elastic pad, it becomes difficult for the suction side roller to smoothly overcome the large gravel and pebbles in the fresh concrete, especially if the lower pad portion is very hard, which may cause the tube to wear out and be damaged prematurely.

[0008] If the one-piece elastic pad is made of a high-hardness elastic material, the first problem can be solved but the second problem cannot be solved. On the other hand, if the one-piece elastic pad is made of a low-hardness elastic material, the second problem can be solved but the first problem cannot be solved.

[0009] The present invention has been proposed in view of the above, and has an object to provide a concrete pump that can solve the above-mentioned conflicting problems of the conventional structure at once with a simple structure. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides a pump case formed in a generally cylindrical shape having a suction port at the bottom of a rear half of an outer peripheral wall and a discharge port at the top, a tube having an intermediate portion extending in an arc shape along the inner peripheral surface of the front half of the outer peripheral wall of the pump case, one end portion extending in a generally tangential direction of the outer peripheral wall through the suction port and the other end portion extending in a generally tangential direction of the outer peripheral wall through the discharge port, a pair of rollers that roll while pressing the intermediate portion of the tube to cause the tube to exert a pumping action, and a pumping mechanism that is provided along the inner peripheral surface of the outer peripheral wall to press the tube. and an elastic pad that can be pressed between the pair of rollers, the pair of rollers being configured to be able to revolve while rotating about the central axis of the pump case with a phase difference of 180 degrees, and with the revolution, one roller releases the pressure and the other roller starts the pressure at approximately the same time, the elastic pad is divided into at least two partial pads including a lower pad closest to the suction port, an upper pad closest to the discharge port, and an intermediate pad connecting the upper pad and the lower pad, The lower pad is disposed in a position corresponding to an area where the other roller rolls on the tube immediately before or immediately after the other roller starts pressing the tube, and the upper pad is disposed in a position corresponding to an area where the one roller rolls on the tube immediately before or immediately after the one roller releases the pressing of the tube. A first feature of the present invention is that the lower pad is made of an elastic material having a lower hardness than the upper pad.

[0011] In addition to the first feature, the present invention has a second feature in that the elastic pad includes, as the partial pad, in addition to the upper pad and the lower pad, at least one intermediate pad connecting the upper pad and the lower pad.

[0012] In addition to the second feature, the present invention has a third feature in that the intermediate pad and the lower pad are made of elastic materials having the same hardness.

[0013] In addition to the second feature, the present invention has a fourth feature in that the lower pad is made of an elastic material having a higher hardness than the intermediate pad.

[0014] In addition to the second feature, the present invention has a fifth feature in that the intermediate pad is made of an elastic material having a harder hardness than the lower pad but not harder than the upper pad. Effect of the Invention

[0015] According to the present invention, the elastic pad is divided into at least two partial pads including a lower pad closest to the intake port and an upper pad closest to the exhaust port. The lower pad is disposed in a position corresponding to an area where the suction side roller rolls on the tube immediately before or after it starts to press the tube, and the upper pad is disposed in a position corresponding to an area where the discharge side roller rolls on the tube immediately before or after it releases the pressure on the tube. The lower pad is made of an elastic material having a lower hardness than the upper pad. As a result, the discharge roller can strongly press the tube between the high-hardness upper pad and the tube, even just before releasing the pressure on the tube (i.e., in the latter half of the discharge process when the pressure load of the fresh concrete increases), so that the fresh concrete can be efficiently pushed out to the downstream side of the tube while preventing backflow, thereby improving the pump efficiency and solving the first problem described above. On the other hand, the suction roller, which is about to start pressing the tube, can easily overcome large gravel and pebbles in the fresh concrete when it starts to pinch the tube between the lower pad because the lower pad has a relatively low hardness, so that early wear and damage to the tube can be effectively suppressed, and the second problem described above can be solved. As a result of the above, it is possible to solve the conflicting problems of the conventional device at once with a simple structure in which the elastic pad is divided and the upper pad is made harder than the lower pad.

[0016] According to the second feature, the elastic pad includes, as the partial pads, an upper pad, a lower pad, and at least one intermediate pad connecting the upper pad and the lower pad, so that the elastic pad can be divided into smaller parts, and therefore, even if the degree of wear varies depending on the hardness of the divided partial pads, the installation location, etc., the partial pads can be replaced frequently and appropriately according to the degree of wear. Also, by dividing the elastic pad into smaller parts, the size of each partial pad can be made smaller, improving the workability when replacing them.

[0017] According to the third feature, since the middle pad and the lower pad are made of elastic material of the same hardness, the lower pad can be set to be relatively harder than when the lower pad is made to be harder than the middle pad. As a result, when the fresh concrete flows back up to the suction side roller when the pressure of the discharge side roller is released, the harder lower pad can effectively prevent the fresh concrete from passing under the suction side roller.

[0018] According to the fourth feature, the lower pad is made of an elastic material having a higher hardness than the intermediate pad, so that the lower pad can be set to a relatively hard material, thereby achieving the same effect as that achieved by the second feature.

[0019] According to the fifth feature, the intermediate pad is made of an elastic material that is harder than the lower pad but not harder than the upper pad, so that the intermediate pad has a relatively high hardness. As a result, even in the middle of the discharge process before the latter half of the discharge process when the pressure load of the fresh concrete increases, the tube can be firmly clamped between the discharge side roller and the relatively hard intermediate pad to push out the fresh concrete. This further improves the effect of preventing backflow of the fresh concrete and further increases the pump efficiency. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is an overall left side view of a concrete pump vehicle according to an embodiment of the present invention; [Diagram 2] Overall right side view of concrete pump truck [Diagram 3] A partially broken enlarged left side view showing the main parts of a concrete pump vehicle, particularly the concrete pump and hopper. [Figure 4] Rear view of the concrete pump and hopper and their peripheral equipment (view taken from the arrow 4 in Figure 1) DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The embodiment of the present invention will be specifically described below with reference to the attached drawings. First, in Fig. 1 and Fig. 2, a concrete pump vehicle V includes a concrete pump CP mounted on a vehicle body F, a hopper H capable of temporarily storing the ready mixed concrete to be supplied to the concrete pump CP, a hopper frame 50 fixed to the rear end of the vehicle body F and extending rearward to fix and support the hopper H so that the front-rear position can be adjusted, a transfer pipe 20 for transferring the ready mixed concrete discharged from the concrete pump CP to a pouring site, and a boom assembly B for connecting and supporting a downstream piping portion 20D of the transfer pipe 20 so that it can be driven up and down to deliver the ready mixed concrete even to a high-altitude pouring site.

[0022] Boom assembly B mainly comprises a number of boom sections arranged in a series and pivotally connected to each other so that they can bend, and a number of hydraulic cylinders for raising and lowering each boom section around the pivotal connections. The base boom section Bb of boom assembly B is supported on a swivel base 11 mounted on the vehicle, and is supported on the vehicle body F via this swivel base 11 so that it can be raised and lowered and can rotate about a vertical axis. Meanwhile, downstream end 20e of transfer pipe 20 is supported on tip boom section Ba, and the base end of a ready mixed concrete blowing pipe (not shown) capable of blowing ready mixed concrete from its tip is detachably attached to the tip of this downstream end 20e.

[0023] The downstream piping section 20D of the transfer pipe 20 is disposed along the multiple boom sections of the boom assembly B, and has multiple joints along the way that can bend in response to the bending motion of the adjacent boom sections. In addition, multiple jacks J that can be extended and retracted up and down are disposed at least at the four corners of the vehicle body F, front, rear, left and right.

[0024] On the other hand, the upstream piping section 20U of the transfer pipe 20 has an upstream end connected to the discharge side of a tube T of the concrete pump CP, which will be described next. The upstream piping section 20U includes a first pipe section 21 that is U-shaped in a plan view and is disposed on the rear side of the concrete pump CP, and a second pipe section 22 that is connected to the downstream end of the first pipe section 21 and extends to the front side of the vehicle body F along the side surface of the pump case C of the concrete pump CP.

[0025] The first pipe section 21 is fixed to and supported by a piping support 30 that protrudes rearward from the rear part of the pump case C, and the second pipe section 22 is fixed to and supported by a plurality of support frames 12 that are fixed at intervals to the vehicle body F. The downstream end of the second pipe section 22 is connected to the downstream piping portion 20D of the transfer pipe 20 via the inside of the swivel base 11.

[0026] The concrete pump CP has a pump case C formed in a cylindrical shape with a central axis extending in the left-right direction and fixed to a vehicle body F, a tube T that is U-shaped in a side view and is provided along the inner circumferential surface of at least the front half outer circumferential wall Ca of the pump case C, a pair of rollers R that squeeze the tube T to cause it to exert a pumping action, and a roller support RS that supports the rollers R rotatably and revolvably around the central axis of the pump case C. The pair of rollers R are arranged with a phase difference of 180 degrees in the rotational direction of the roller support RS.

[0027] The pump case C is divided into a cylindrical outer wall Ca and a pair of left and right disc-shaped outer plates Cs whose outer peripheries are detachably connected (e.g., bolted) to both left and right ends of the outer wall Ca, hermetically sealing the left and right open ends of the outer wall Ca.

[0028] The tube T is flexible and elastic, and is made of a strong elastic material that will not break even when it is squeezed by the rollers R and performs a pumping function for a long period of time. An elastic pad P that extends in the circumferential direction is attached to at least the inner peripheral surface of the front half of the outer peripheral wall Ca of the pump case C so as to pinch the tube T between the rollers R that revolve while rotating. This elastic pad P is divided into an upper pad Pt, first and second intermediate pads Pf1, Pf2, and a lower pad Pb that are adjacent to each other in the circumferential direction of the outer peripheral wall Ca and are arranged in order from top to bottom, and each of the pads Pt, Pf1, Pf2, and Pb is molded into a predetermined shape from an elastic material (e.g., rubber, etc.).

[0029] The upper pad Pt is located closest to a discharge port Co of the pump case C, which will be described later, and is disposed in a position corresponding to the area where the discharge side roller R rolls on the tube T from immediately before or after the discharge side roller R releases the pressure on the tube T. The lower pad Pb is located closest to a suction port Ci of the pump case C, which will be described later, and is disposed in a position corresponding to the area where the suction side roller R rolls on the tube T from immediately before or after the suction side roller R starts to press the tube T.

[0030] The upper pad Pt is made of an elastic material having the highest hardness among the elastic pads P, and the lower pad Pb is made of an elastic material having a lower hardness than the upper pad Pt. Moreover, the lower pad Pb is formed thicker than the upper pad Pt and the first and second intermediate pads Pf1, Pf2, which, together with the effect of making the lower pad Pb of relatively low hardness, makes it easier for the suction side roller R to overcome large gravel and pebbles in the ready-mixed concrete when it begins to pinch the tube T between itself and the lower pad Pb.

[0031] In the embodiment, the thickness of the rear half of the upper pad Pt (i.e., the area immediately after the discharge side roller R releases the pressure on the tube T) is gradually reduced as it approaches the rear end. The rear half of the upper pad Pt may be formed to have the same thickness as the front half.

[0032] The hardness of the elastic material constituting the first and second intermediate pads Pf1, Pf2 can be selected from several combination patterns in relation to the hardness of the upper pad Pt and the lower pad Pb, as shown in Table 1 below. In any of the combination patterns, the upper pad Pt has the elastic material hardness KT set to the same hardness (i.e., a hardness that can achieve the effect of preventing backflow of fresh concrete from the tube T that is clamped between the upper pad Pt and the discharge-side roller R in the latter half of the discharge process).

[0033] [Table 1]

[0034] Thus, Example 1 corresponding to the first pattern has the hardness KF1 of the elastic material of the first and second intermediate pads Pf1, Pf2 set to be the same as the hardness KB1 of the elastic material of the lower pad Pb, which corresponds to the second and third features of the present invention.

[0035] In addition, Example 2 corresponding to the second pattern has the hardness KF2 of the elastic material of the first and second intermediate pads Pf1, Pf2 set lower than the hardness KB2 of the elastic material of the lower pad Pb, which corresponds to the second and fourth features of the present invention.

[0036] Furthermore, Example 3 corresponding to the third pattern has the hardness KF3 of the elastic material of the first and second intermediate pads Pf1, Pf2 set to a hardness higher than the hardness KB3 of the elastic material of the lower pad Pb but not higher than the hardness KT of the elastic material of the upper pad Pt (i.e., the hardness is the same as or lower than the hardness KT of the upper pad Pt), which corresponds to the second and fifth features of the present invention.

[0037] Although the intermediate pad has been exemplified as having an upper and lower two-part structure consisting of the first and second intermediate pads Pf1 and Pf2, it may be an integral (hence single) intermediate pad instead of this divided structure.

[0038] In addition, in the second and third embodiments, the hardness of the elastic material of the first and second intermediate pads Pf1 and Pf2 may be the same or different. In the latter case, in which the hardness is different, it is preferable to make the elastic material of the upper first intermediate pad Pf1 harder than the elastic material of the lower second intermediate pad Pf2 in order to prevent backflow of the fresh concrete during the discharge process.

[0039] 3, the elastic pad P of the embodiment is joined to the inner peripheral surface of the outer peripheral wall Ca of the pump case C via a band-shaped interior plate 37 curved along the inner peripheral surface. In this case, for example, if a pad assembly formed by joining (e.g., bonding, baking, etc.) the elastic pad P (i.e., the upper pad Pt, the first and second intermediate pads Pf1, Pf2, and the lower pad Pb) to the interior plate 37 is assembled in advance, it can be inserted into the pump case C and joined (e.g., bolted).

[0040] The pads Pt, Pf1, Pf2, and Pb of the elastic pad P may be joined directly to the inner circumferential surface of the outer circumferential wall Ca of the pump case C (that is, without the interior plate 37 therebetween).

[0041] The discharge end To of the tube T extends in a substantially tangential direction (rearward) of the outer peripheral wall Ca through a discharge port Co provided in the upper part of the pump case C facing rearward, and is detachably connected to the upstream piping section 20U of the transfer pipe 20 by a conventionally known coupling means JT. The coupling means JT has, for example, a cylindrical socket 23 for fitting the discharge end To of the tube T to its outer periphery, a coupling (bolt and nut 25 in the illustrated example) for detachably coupling between a flange section 23f at the outer end of the socket 23 and a flange section 24 at the upstream end of the upstream piping section 20U, and a fastener for fastening the outer periphery of the discharge end To of the tube T in the direction of reducing the diameter. The fastener has, for example, a pair of clamp members 26 for sandwiching the outer periphery of the discharge end To between them, and a bolt and nut 27 for fastening the clamp members 26 so as to attract each other.

[0042] On the other hand, the suction end Ti of the tube T extends in a direction approximately tangential to the outer wall Ca (rearward) through an intake port Ci provided rearward in the lower part of the pump case C, and is connected to the downstream end of the outlet pipe Ho of the hopper H described later.

[0043] The roller support RS is rotatably supported on the left and right outer plates Cs of the pump case C, and is rotationally driven by a rotation drive device (not shown) provided between the pump case C and the roller support RS. A pair of guide rollers 35 are rotatably supported on the roller support RS, which are disposed forward of the rollers R in the forward rotation direction (clockwise in FIG. 3) of the roller support RS and sandwich the tube T from the left and right, and these guide rollers 35 suppress meandering and lateral deviation of the tube T.

[0044] In the pump case C of the embodiment, the inner peripheral surface of the front half of the outer peripheral wall Ca is formed into an arc surface with a central angle that is a predetermined angle α larger than 180 degrees, as is clear from Fig. 3. This makes it possible to delay the timing when the pressure of the roller R against the tube T is released (the timing when discharge ends), and effectively prevents the backflow of fresh concrete when the pressure is released. Also, by making the central angle of the inner peripheral surface of the outer peripheral wall Ca somewhat larger in this way, the opening direction of the discharge port Co of the pump case C faces downward and rearward, and accordingly, the discharge end To of the tube T also extends rearward, inclining downward and rearward.

[0045] The hopper H is formed in a tank shape that is open at the top and extends in the left-right direction, and an outlet pipe Ho that can discharge the fresh concrete in the hopper H is connected and fixed to the bottom of the hopper H. Also, an agitator 28 is disposed in the hopper H to agitate the fresh concrete charged therein to make it less likely to harden, and as is clear from Fig. 4, the agitator 28 is equipped with a plurality of agitator blades 28b that can rotate within the hopper H and a rotary drive unit 28a that drives and rotates the agitator blades 28b.

[0046] A pair of left and right support legs Ha extending in the front-rear direction are provided downwardly on the lower part of the hopper H, and both support legs Ha are placed and supported on both left and right sides of the upper surface of a rectangular hopper frame 50 so as to be slidable only in the front-rear direction. Between at least one of the support legs Ha and the hopper frame 50, there are interposed a hydraulic cylinder 53 capable of driving the support leg Ha (and therefore the hopper H) back and forth, and a locking mechanism LA for releasably locking the support leg Ha to the hopper frame 50 when the hopper H is in the forward position (i.e., the normal use position) shown in Fig. 3.

[0047] The outlet pipe Ho of the hopper H extends downward from the bottom surface of the hopper H, then curves and extends forward, and its extending end, i.e., its downstream end, is detachably connected to the suction end Ti of the tube T by a conventionally known connecting means JT'. Note that this connecting means JT' has the same structure as the connecting means JT between the discharge end To of the tube T and the transfer pipe 20 described above, so a detailed explanation will be omitted and it will merely be given the same reference numeral as the connecting means JT.

[0048] The pump case C is equipped with a vacuum device (not shown) for creating a negative pressure in its internal space, and this negative pressure helps the tube T, located on the rear side of the discharge roller R in the revolution direction, to automatically restore itself by its own elastic restoring force (therefore, the fresh concrete in the hopper H is sucked into the tube T). And, at each of the adjacent portions of the pump case C to the suction port Ci and the discharge port Co, the base ends of conventionally known boot-shaped seal cylinders 29 for preventing the negative pressure from leaking from the suction port Ci and the discharge port Co are respectively airtightly fixed, and each seal cylinder 29 is configured so that its inner peripheral surface can be airtightly fitted and pressed against the outer periphery of the suction end Ti and the discharge end To of the tube T, respectively.

[0049] An operation panel 55 is provided on either the left or right side of the pump case C, allowing an operator outside the vehicle to issue operating commands to the concrete pump CP, boom assembly B, and other operating equipment mounted on the concrete pump vehicle V. A similar operation panel is also provided in the driver's seat.

[0050] In addition, the base of a screen S, which is rotatable between a closed position that covers the open top surface of the hopper H and an open position that stands up from the closed position, is supported on the upper part of the front wall of the hopper H. This screen S has a screen main body Sm configured in a lattice frame shape to prevent people and large foreign objects from falling into the hopper H, and a rotating support shaft Sj fixed to the base of the screen main body Sm. Both ends of the rotating support shaft Sj are detachably and rotatably fitted into and supported by clamp support mechanisms 51 provided on the upper parts of the left and right side walls of the hopper H.

[0051] Also, disposed on one front side of the hopper H is an opening / closing sensor 40 having a detection unit 42 capable of detecting the open / closed state of the screen S, and a sensor cover 41 fixed to the hopper H below the transfer pipe 20 and covering the detection unit 42. The sensor cover 41 is fixed and supported on a support base 43 fixed to the upper part of one side wall of the hopper H, and prevents ready mixed concrete scattered from inside the hopper H from getting onto the detection unit 42. Also, the detection unit 42 is equipped with a dog 42d fixed to one end of the rotation support shaft Sj of the screen S and rotating integrally with the rotation support shaft Sj, and a detection element 42s capable of detecting the rotation displacement angle of the dog 42d (and therefore the screen S) without contact.

[0052] A splash guard G for preventing the scattering of fresh concrete from inside the hopper H toward the pump case C is supported on the upper part of the front wall of the hopper H so as to be able to rotate up and down between an upright position where the splashing can be prevented and a lying-down position where the splash guard G is lying down on the open top side of the hopper H. A locking mechanism 54 for detachably locking the base of the splash guard G to fix the splash guard G in the upright position is provided on the front wall of the hopper H. The splash guard G has a cutout portion Gc that is open at the top so that the rearward extending pipe portion 21a and the piping support body 30 can pass through in the front-rear direction when the splash guard G is in the upright position.

[0053] Furthermore, when the hopper H is moved backward on the hopper frame 50 for replacing the tube T or the like, the splash guard G can be laid down and held in the closed position in advance to prevent interference with the upstream piping portion 20U of the transfer pipe 20. When laying the splash guard G down and rotating it to the closed position, the screen S is removed from the hopper H in advance to prevent interference with the splash guard G.

[0054] Next, the operation of the embodiment will be described.

[0055] Ready-mixed concrete is poured into the hopper H by a mixer truck or the like, where it is temporarily stored while being agitated by the agitator 28. In this state, when the roller support RS is rotated forward (clockwise in FIG. 3), the pair of rollers R rotate in conjunction with this and revolve around the central axis of the pump case C. As a result, each roller R rolls in the circumferential direction while squeezing the tube T between itself and the inner peripheral surface (more specifically, the elastic pad P) on the front half side of the outer peripheral wall Ca of the pump case C, and at this time, the pump action (i.e., the action of pushing out ready-mixed concrete from the tube T) is continuously repeated at the pressing timing such that one roller R releases the pressure on the tube T and the other roller R starts pressing the tube T at the same time.

[0056] The ready-mixed concrete discharged from the tube T is pumped through the transfer pipe 20 and can be blown out from a ready-mixed concrete blowing pipe (not shown) attached to the downstream end 20e of the transfer pipe 20. Therefore, by appropriately bending and extending each boom section of the boom assembly B to move the ready-mixed concrete blowing pipe together with the downstream piping section 20D of the transfer pipe 20 to the ready-mixed concrete pouring location at the construction site of a building or the like, the concrete pump CP can pump and supply the ready-mixed concrete even if the pouring location is at a high altitude.

[0057] Meanwhile, the elastic pad P in the embodiment (i.e., Examples 1 to 3) is divided into a lower pad Pb closest to the suction port Ci, an upper pad Pt closest to the discharge port Co, and first and second intermediate pads Pf1 and Pf2 connecting the upper pad Pt and the lower pad Pb, and the lower pad Pb is made of an elastic material with a lower hardness than the upper pad Pt. As a result, the discharge side roller R can strongly press the tube T between itself and the high-hardness upper pad Pt even just before releasing the pressure on the tube T (i.e., in the latter half of the discharge process when the pressure load of the fresh concrete increases), so that the fresh concrete can be efficiently pushed out to the downstream side of the tube T while preventing its backflow, and the pump efficiency can be improved, and therefore the first problem described above can be solved.

[0058] On the other hand, when the suction side roller R begins to press against the tube T and starts to clamp the tube T between it and the lower pad Pb, the relatively low hardness of the lower pad Pb makes it easier for the roller Pb to smoothly overcome large gravel and pebbles in the fresh concrete, thereby effectively suppressing premature wear and damage to the tube T, thereby solving the second problem mentioned above.

[0059] As a result, according to the first to third embodiments, the first and second conflicting problems of the conventional device can be solved at once with a simple structure in which the elastic pad P is divided and the upper pad Pt is made harder than the lower pad Pb.

[0060] In addition, the elastic pad P of Examples 1 to 3 includes, as a plurality of partial pads that are divided, an upper pad Pt and a lower pad Pb, as well as at least one intermediate pad Pf1, Pf2 that connects the upper pad Pt and the lower pad Pb, so that the elastic pad P can be divided more finely, and therefore, even if the degree of wear varies depending on the hardness and installation location of the divided partial pads Pt, Pb, Pf1, Pf2, the partial pads can be replaced frequently and appropriately according to the degree of wear. Moreover, by dividing the elastic pad P more finely in this way, the size of each partial pad Pt, Pb, Pf1, Pf2 can be made smaller, making handling during replacement easier and improving workability.

[0061] In particular, in the first embodiment, the intermediate pads Pf1, Pf2 and the lower pad Pb are made of elastic materials of the same hardness, so the lower pad Pb can be set to be relatively harder than the lower pad Pb having a lower hardness than the intermediate pads Pf1, Pf2. As a result, when the fresh concrete flows back to the suction side roller R due to the release of the pressure on the discharge side roller R, the harder lower pad Pb can effectively prevent the fresh concrete from passing under the suction side roller R.

[0062] In particular, in the second embodiment, the lower pad Pb is made of an elastic material having a higher hardness than the intermediate pads Pf1 and Pf2, so that the lower pad Pb can be set to a relatively high hardness. Therefore, it is possible to achieve the same effect as that of the second embodiment.

[0063] In particular, in Example 3, the intermediate pads Pf1, Pf2 are made of an elastic material that is harder than the lower pad Pb but not harder than the upper pad Pt, so the hardness of the intermediate pads Pf1, Pf2 is relatively high. As a result, even in the middle of the discharge process before the latter half of the discharge process when the pressure load of the fresh concrete increases, the tube T can be strongly pressed between the discharge side roller R and the relatively hard intermediate pads Pf1, Pf2 to push out the fresh concrete, further improving the effect of preventing backflow of the fresh concrete.

[0064] Meanwhile, the elastic pad P in Examples 1 to 3 has a divided structure including an upper pad Pt, a lower pad Pb, and at least one intermediate pad Pf1, Pf2 between the upper pad Pt and the lower pad Pb as a plurality of partial pads that divide it. However, according to the first feature of the present invention, although not shown in the figures, it is also possible to implement another embodiment in which the elastic pad P has only the upper pad Pt and the lower pad Pb as partial pads (i.e., the intermediate pads Pf1, Pf2 are omitted and the elastic pad P has an upper and lower two-part structure).

[0065] In this alternative embodiment, the gap (division position) between the upper pad Pt and the lower pad Pb adjacent thereto in the circumferential direction may be set at a position that divides the pump case C into upper and lower halves, or may be set at a position offset upward or downward from the upper and lower halves.

[0066] Although the embodiment of the present invention has been described above, the present invention is not limited to the embodiment, and various embodiments can be implemented within the scope of the present invention.

[0067] For example, in the embodiment, the lower pad Pb is formed thicker than the upper pad Pt and the first and second intermediate pads Pf1 and Pf2, but the thickness of each pad can be selected appropriately, and for example, the lower pad Pb may be formed to have the same thickness as the other pads Pt, Pf1, and Pf2. Alternatively, the intermediate pads Pf1 and Pf2 may be formed to be slightly thicker than the upper pad Pt.

[0068] In addition, in the above embodiment, an example was given of an arc-shaped range on the inner surface of the pump case C, along which the tube T is aligned, extended to a central angle of 180 degrees or more in order to suppress backflow of fresh concrete at the end of the discharge stroke by the roller R and thereby increase the durability of the tube T, but the arc-shaped range may also be set to a central angle of 180 degrees. [Explanation of symbols]

[0069] CP····Concrete pump C·····Pump case Ca...Pump case outer wall Ci...Inhalation port Co...Discharge port P·····Elastic pad Pb...Lower pad as partial pad Pt...Upper pad as partial pad Pf1, Pf2: The first and second intermediate pads constituting the intermediate pad as a partial pad R...Roller T...Tube

Claims

1. The pump case (C) is formed in a generally cylindrical shape having a suction port (Ci) at the bottom of the rear half of an outer peripheral wall (Ca) and a discharge port (Co) at the top, and a tube (T) having an intermediate portion extending in an arc shape along the inner peripheral surface of the front half of the outer peripheral wall (Ca) of the pump case (C), one end portion extending in a generally tangential direction of the outer peripheral wall (Ca) through the suction port (Ci) and the other end portion extending in a generally tangential direction of the outer peripheral wall (Ca) through the discharge port (Co), and a pump (T) which rolls while pressing the intermediate portion of the tube (T) to rotate the tube (T). a pair of rollers (R) for causing a tube (T) to exert a pumping action, and an elastic pad (P) provided along at least the inner peripheral surface of the front half of the outer peripheral wall (Ca) and capable of clamping the tube (T) between the rollers (R), the pair of rollers (R) are configured to be able to revolve around the central axis of the pump case (C) while rotating with a phase difference of 180 degrees, and in accordance with the revolution, one roller (R) releases the pressure and the other roller (R) starts the pressure at approximately the same time, The elastic pad (P) is divided into at least two partial pads (Pb, Pt, Pf1, Pf2) including a lower pad (Pb) closest to the suction port (Ci) and an upper pad (Pt) closest to the discharge port (Co), the lower pad (Pb) is arranged corresponding to an area where the other roller (R) rolls on the tube (T) from immediately before to immediately after it starts pressing against the tube (T), and the upper pad (Pt) is arranged corresponding to an area where the one roller (R) rolls on the tube (T) from immediately before to immediately after it releases the pressing against the tube (T), A concrete pump characterized in that the lower pad (Pb) is made of an elastic material having a lower hardness than the upper pad (Pt).

2. The concrete pump according to claim 1, characterized in that the elastic pad (P) includes, as the partial pads, the upper pad (Pt) and the lower pad (Pb), as well as at least one intermediate pad (Pf1, Pf2) connecting between the upper pad (Pt) and the lower pad (Pb).

3. The concrete pump according to claim 2, wherein the intermediate pads (Pf1, Pf2) and the lower pad (Pb) are made of elastic materials having the same hardness.

4. 3. The concrete pump according to claim 2, wherein the lower pad (Pb) is made of an elastic material having a higher hardness than the intermediate pads (Pf1, Pf2).

5. The concrete pump according to claim 2, characterized in that the intermediate pads (Pf1, Pf2) are made of an elastic material having a harder hardness than the lower pad (Pb) but not greater than the hardness of the upper pad (Pt).

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