Jaw crusher

Abstract: A jaw crusher is disclosed with a tooth plate (2,3) structure which is capable of effectively crushing a non-rigid object, for example, a lump of asphalt, without causing such an object to stick to the area between a cheek plate and a fixed tooth plate or a movable tooth plate. The movable tooth plate (3) is provided with cutting projections (61). A plate-shaped object is first broken by the cutting projections (61) and then crushed by intermediate projections (62).

Description: The present invention relates to a jaw crusher according to the preamble of claim 1. Jaw crushers are known and used as machines for breaking rocks, asphalt pavement wastes, concrete scraps, etc. into pieces of desired size. These days, a large amount of concrete scrap and asphalt pavement waste are produced by dismantling of concrete buildings, repair of asphalt pavements, etc. Treatment of these wastes, particularly in urban areas, gives rise to a social problem because of the generation of noise and dust during the treatment, difficulty in securing a place for dumping wastes, a high cost of waste transportation, etc. For this reason, these wastes are desired to be speedily treated and reused at or near the site where the wastes are produced, as much as possible. The US 2 122 033 discloses a jaw crusher having a fixed and a movable tooth plate. Both of the tooth plates are provided with cutting projections and crushing projections being provided substantially in the middle between each pair of cutting projections and being lower than the cutting projections. The FRA 588 108 also discloses a jaw crusher having tooth plates provided with cutting projections and lower crushing projections between them. The projections at the edges of the plates are shown in the drawings as having a vertical surface at the outer side and a slant surface on the inner side. The FRA 2 483 256 shows and describes a jaw crusher. This jaw crusher does not have tooth plates but a concave and a convex plate forming a chamber. The chamber has a pre-crushing zone and a final crushing and delivering zone in which the crushed objects where the broken objects may be delivered to the bottom and to the sides while in the pre-crushing zone the sides of the chamber are closed by side walls. This said to comply with the object to avoid unnecessary additional crushing of particles of a size do not require further crushing. To crush non-rigid objects, for example, asphalt, it has been conventional practice to use tooth plate structures shown in Figs. 7(a) and 7(b), which are designed to crush rigid objects, e.g., aggregates, concrete, etc., or a tooth plate structure shown in Fig. 7(c), which is devised to crush non-rigid objects. However, in these prior arts, a groove-shaped recess 86 is defined between a cheek plate 80 that is attached to a side plate of a machine frame and a fixed tooth plate 85a that is attached to the machine body, as shown in Figs. 7(a), 7(b) and 7(c). For this reason, a non-rigid object is pressed by a movable tooth plate 85b that is attached to a swing frame in such a manner that the object is confined in the recess 86, resulting in the object sticking to the cheek plate 80, the fixed tooth plate 85a and the movable tooth plate 85b in the form of a fixed object Ga. The fixed object Ga obstructs the falling of other objects of crushing and hence lowers the crushing capacity. In the meantime, a tooth plate structure which is designed to break an object by bending is known. For example, Japanese Patent Laid-Open (KOKAI) No. 60-147252 (Date of public disclosure: August 3, 1985; Applicant: Kawasaki Jukogyo K.K.) proposes a tooth plate structure which is designed to cut blast furnace slag by bending. However, this tooth plate structure is adapted for breaking by bending only and is not very effective in crushing. It is an object of the present invention to provide a jaw crusher with a tooth plate structure which enables even a non-rigid object for example a lump of asphalt, to be efficiently crushed without sticking to the area between the cheek plate and the fixed tooth plate. To comply with this object, the invention is characterized by the features of the characterising portion of claim 1. According to one aspect of the present invention, there is provided a jaw crusher for breaking a non-rigid object comprising: a body; a fixed tooth plate which is secured to the body; a movable tooth plate which is swingably provided at an acute angle to the fixed tooth plate to provide therebetween a crushing space for breaking an object which is to be crushed; a swing jaw to which the movable tooth plate is secured; a driving mechanism for swinging the swing jaw; a motor for driving the driving mechanism; relatively high cutting projections which are provided on either the fixed or movable tooth plate at a predetermined pitch to bend and cut the object which is put between the fixed and movable tooth plates; crushing projections each of which is provided substantially at the middle between each pair of adjacent cutting projections, the crushing projections being lower than the cutting projections; and projections which are provided on the other of the fixed and movable tooth plates at a predetermined pitch. A cheek plate is provided at both sides of the fixed tooth plate and the movable tooth plate. The edge projections at either end of the movable tooth plate and the fixed tooth plate have a vertical surface adjacents the cheek plate and a slant surface on the inner side. The tooth plate structure of the present invention effects breaking by bending and, at the same time, cutting by the effect of wedge and then performs breaking by crushing. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front view of the jaw crusher with a pass-through preventing device Fig. 2 is a side view of the jaw crusher shown in Fig. 1; Fig. 3 is a sectional view of a first embodiment of the tooth plate structure according to the present invention; Fig. 4 is a plan view of the movable tooth plate shown in Fig. 3. Fig. 5 is a plan view of the fixed tooth plate shown in Fig. 3; Fig. 6(a) is a sectional view of a second embodiment of the tooth plate structure; Fig. 6(b) is a sectional view of a third embodiment of the tooth plate structure; and Figs. 7(a), 7(b) and 7(c) are sectional views of conventional tooth plate structures. One embodiment of the present invention will be described below with reference to the accompanying drawings. Fig. 1 is a front view of a crusher that is generally called "single-toggle type jaw crusher" (hereinafter referred to as "jaw crusher"). Fig. 2 is a side view of the jaw crusher as viewed from the left-hand side of Fig. 1. The jaw crusher has a body 1 that is made of steel plate. A fixed tooth plate 2 is secured to a wall surface inside the body 1. A movable tooth plate 3 is disposed in opposing relation to the fixed tooth plate 2. A wedge-shaped crushing space 4 is defined between the fixed and movable tooth plates 2 and 3. The movable tooth plate 3 is secured to the front side of a swing jaw 5. The upper end of the swing jaw 5 is rotatably supported by an eccentric shaft 6. The lower end of the swing jaw 5 is supported by the forward end of a toggle plate 7 which abuts against it. The rear end of the toggle plate 7 is supported by the body 1. The eccentric shaft 6 is supported by the body 1 through bearings 8. A flywheel 9 is attached to one end of the eccentric shaft 6, and a V-belt pulley 10 is secured to the other end thereof. The V-belt pulley 10 is driven to rotate by a motor (not shown) through a V-belt. The eccentric shaft 6 is rotated in response to the rotation of the V-belt pulley 10. In response to the rotation of the eccentric shaft 6, the swing jaw 5 moves up and down as well as back and forth. Since the swing jaw 5 is supported by the toggle plate 7 from the back, the back-and-forth motion of the swing jaw 5 results in approximately circular motion along a circle the radius of which is defined by the toggle plate 7. The swing jaw 5 performs the vertical motion and the circular motion at the same time in response to the rotation of the eccentric shaft 6. The forward end of a rod 11 is rotatably attached to the rear portion of the lower end of the swing jaw 5 through a joint. A washer 14 is attached to the rear end of the rod 11 by a nut. A coil spring 12 is interposed between the washer 14 and a bracket 13. Since the bracket 13 is secured to the body 1, the rod 11 constantly pulls the swing jaw 5 rearwardly. Accordingly, the swing jaw 5 performs the above-described approximately circular motion without separating from the forward end of the toggle plate 7. Figs. 3, 4 and 5 show the crushing tooth plates of the jaw crusher according to the invention. Fig. 3 is a sectional view of the fixed and movable tooth plates 2 and 3 in their assembled state; Fig. 4 is a plan view of the movable tooth plate 3; and Fig. 5 is a plan view of the fixed tooth plate 2. As shown in Figs. 6 and 7, the movable tooth plate 3 comprises edge projections 60 that define left and right edges of a crushing face 50a, cutting projections 61 that first roughly cut a lump of asphalt G, for example, and groups 62 of intermediate crushing projections that break the pieces of the cut lump G into smaller pieces of appropriate size. The top portion 63 of each edge projection 60 has a substantially semicircular cross-sectional configuration. One side of each edge projection 60 has a vertical surface 64 that extends parallel to the direction of swing of the movable tooth plate 3. The other side surface of the projection 60 is defined by a slant surface 65 that is stepwisely slanted (i.e., with two different angles of inclination) toward the center of the crushing face 50a. Each cutting projection 61 has a height h 1 from the root, which is greater than the height h 2 of the edge projections 60. In addition, the cutting projections 61 have acute-angled top portions 66 that are disposed at a constant pitch P along the crushing face 50a. An intermediate crushing projection group 62 is disposed between each pair of adjacent cutting projections 61. The height of the intermediate crushing projections 62 is lower than that of the edge projections 60. The top portion 67 of each intermediate crushing projection has a substantially semicircular cross-sectional configuration. Each intermediate crushing projection group 62 comprises three projections each having a circular cross-section at the distal end. Among the three projections, only the central projection 62a is slightly higher (h 3 ) than the other projections 62b. The central projection 62a is disposed at the middle between each pair of adjacent cutting projections 61. In other words, the cutting projections 61 and the central projections 62a are alternately disposed at a pitch of P/2. Fixed tooth plate The fixed tooth plate 2, which is disposed in opposing relation to the movable tooth plate 3, is formed such that each projection of the movable tooth plate 3 can function effectively to attain its own purpose. As shown in Figs. 3 and 5, a projection 71 is disposed at each edge of a crushing face 52a. The top portion 70 of the projection 71 has a substantially semicircular cross-sectional configuration. One side of the projection 71 is defined by a slant surface 73 that is slanted toward the center of the crushing face 52a. Projections 74 are formed in the intermediate portion of the crushing face 52a of the fixed tooth plate 2 at a constant pitch and with the same height. The top portion 75 of each projection 74 has a semicircular cross-sectional configuration. Each cutting projection 61 of the movable tooth plate 3 faces the root between a pair of adjacent projections 74 of the fixed tooth plate 2. In each intermediate crushing projection group 62, only the central projection 62a faces the top portion 75 of a projection 74. The projection 62b, which is disposed at each side of the central projection 62a, faces the root between a pair of adjacent projections 74. Operation The jaw crusher of this embodiment has the above-described tooth plate structure for crushing a non-rigid object, and the movable tooth plate 3 is attached to the swing jaw 5, while the fixed tooth plate 2 is attached to the body 1. In the assembled state, the vertical surfaces 64 of the edge projections 60, which are at the left and right ends of the movable tooth plate 3, and the vertical surfaces 72 of the projections 71, which are at the left and right ends of the fixed tooth plate 3, are disposed extremely close to the surfaces of associated cheek plates 80, so that the top portions 63 and 70 of these projections are in close proximity to the cheek plates 80, as shown in Fig. 3. When the movable tooth plate 3 is swung, the cutting projections 61, which are the highest (h 1 ), first approach the fixed tooth plate 2 and then the intermediate crushing projection groups 62 do. A lump G of asphalt thrown in is first bent between the cutting projections 61 and the projections 74 of the fixed tooth plate 2 and cut by the wedge effect of the cutting projections 61. In other words, the cutting projections 61 perform cutting by bending and cutting by the wedge action. Thereafter, the pieces of the lump G thus cut are further cut by the cooperation of the central projections 62a in the intermediate crushing projection groups 62 and the projections 74 of the fixed tooth plate 2 and are then further broken into smaller pieces by the crushing projections 62b at both sides of each central projection 62a. The edge projections 71 of the fixed tooth plate 2 cooperate with the edge projections 60 of the movable tooth plate 3 to break an object of crushing, for example, a lump G of asphalt, which is near the associated cheek plates 80. For this reason, the object G is always pushed toward the center of the tooth plate structure by the slant surface 65 of the edge projection 60 of the movable tooth plate 3 and the slant surface 73 of the projection 71 provided at each edge of the fixed tooth plate 2. Accordingly, there is no possibility of either side of the crushing tooth plate structure being clogged with the object G. As has been described above, since according to this embodiment flexural projections and crushing projections are alternately provided on the crushing face at a constant pitch, a non-rigid object, for example, a lump of asphalt, can be efficiently crushed. In addition, since the projections 60 and 71 are provided at the left and right ends of the movable and fixed tooth plates 3 and 2 in opposing relation to each other and a vertical surface is formed on the side of each of the projections 60 and 71 which is closer to the associated cheek plate 80, a relatively soft object of crushing which is near the cheek plate 80 is pushed toward the center of the tooth plate structure, so that there is no possibility of such an object sticking to the area between the cheek plate and the crushing tooth plates. In other words, the slant surfaces 65 and 73 always act in such a manner as to move the object of crushing toward the center of the crushing tooth plates. Accordingly, it is possible to facilitate the falling of the object and hence improve the crushing capacity of the jaw crusher. Second and third embodiments of fixed and movable tooth plates Although one embodiment of the fixed and movable tooth plates according to the present invention has been detailed with reference to the drawings, it should be noted that the arrangements of the fixed and movable tooth plates are not necessarily limited to those in this embodiment and that various changes and modifications may be imparted thereto without departing from the gist of the present invention as defined by the claims. Fig. 6(a) shows a second embodiment, in which an intermediate projection 62a with a height h 2 is provided at the middle between a pair of adjacent cutting projections 61 with a height h 1 , that is, the cutting projections 61 and the intermediate projections 62a are alternately disposed at a pitch of P/2. The heights of the two different kinds of projection are set to satisfy the relation of h 1 >h 2 . Fig. 6(b) shows a third embodiment, in which a second cutting projection 61a is provided at the middle between each pair of adjacent cutting projections 61. The height h 2 of the second cutting projections 61a is lower than the height h 1 of the cutting projections 61. In addition, an intermediate projection 62a is provided at the middle (P/4) between a cutting projection 61 and a neighboring second cutting projection 61a. The height h 3 of the intermediate projections 62a is lower than the height h 2 of the second cutting projections 61a. The relationship between the heights h 1 , h 2 and h 3 is h 1 >h 2 >h 3 . Although in the above-described embodiment each edge projection 60 of the movable tooth plate 3 is formed with a slant surface 65 that is stepwisely slanted (i.e., with two different angles of inclination), it should be noted that the configuration of the slant surface 65 is not necessarily limitative thereto and that the slant surface 65 may have any desired configuration.

Claims: A jaw crusher for breaking a non-rigid object comprising a) a body, b) a fixed tooth plate (2) which is secured to said body, d) a movable tooth plate (3) which is swingably provided at an acute angle to said fixed tooth plate to provide therebetween a crushing space (4) for breaking an object which is to be crushed, e) a swing jaw to which said movable tooth plate (3) is secured and a driving mechanism for swinging the swing jaw f) a motor for driving said driving mechanism, g) relatively high cutting projections (61) which are provided on one of said fixed tooth plate (2) and said movable tooth plate (3) at a predetermined pitch to bend and cut said object which is put between said fixed plate and said movable tooth plate, h) crushing projections (62), each of which is provided substantially at the middle between each pair of adjacent cutting projections (61) of said crushing projections, said crushing projections being lower than said cutting projections, i) projections (75) which are provided on the other of said fixed tooth plate (2) and said movable tooth plate (3) at a predetermined pitch, j) a cheek plate (80) which is provided at each side of said fixed tooth plate and said movable plate, k) first edge projections (60), each of which is provided at either end of said movable tooth plate (3), each of said first edge projections having a first vertical surface (64) and a first slant surface (65), wherein said first vertical surface (64) is formed on the side which is closer to said cheek plate (80), while said first slant surface acts (65) to move an object to be crushed toward the center of said movable plate, the top portion of each of said first edge projections (60) being in close proximity to said cheek plate (80). l) second edge projections (71), each of which is provided at either end of said fixed tooth plate (2), each of said second edge projections having a second vertical surface (72) and a second slant surface (73), wherein said second vertical surface (72) is formed on the side which is closer to said cheek plate (80), while said second slant surface acts to move an object to be crushed toward the center of said fixed plate, the top portion of each of said second edge projections being in close proximity to said cheek plate, characterized by m) the respective top portions (63,70) of the first and second edge projections (60,71) having a substantially semicircular cross-sectional configuration, allowing the first and second edge projections (60,71) to break an object to be crushed which is near the associated cheek plate (80). n) the first and second edge projections (60,71) having a constant cross-section over the whole length of the respective tooth plate (2,3).

Inventors: HIRAKAWA MASANAO, HIRANO KAZUJISA, ISEBABA YOSHIHIRO, KITSUKAWA TOMOHIRO, HIRAKAWA, MASANAO, HIRANO, KAZUJISA, ISEBABA, YOSHIHIRO, KITSUKAWA, TOMOHIRO
Applicants: NAKAYAMA IRON WORKS LTD, NAKAYAMA IRON WORKS, LTD.
Application year: 1991
Main classification: B02C1
IPC codes: B02C1