TROLLEY TRANSFER UNIT FOR TUNNEL FURNACE

Abstract: A trolley transfer unit for a tunnel furnace is to be used between trolleys when ceramic sintered products are loaded onto and unloaded from the trolleys in sintering the products in the tunnel furnace. The trolley transfer unit comprises a bar member (11) for connecting the two trolleys at a predetermined spacing, protrusions (12) provided at both ends of the bar member (11) for engaging the trolleys to be connected, and a support bar (13) secured to the bar member (11) and engaging a frame of the other trolley to support the bar member.

Description: This invention relates to tunnel kiln trolleys for a tunnel furnace or tunnel kiln, and more particularly to a connection to be used between trolleys when ceramic sintered products are loaded onto or unloaded from trolleys. As shown by way of example in Fig. 1, with a trolley transfer system for a tunnel furnace hitherto used, there are provided a tunnel furnace 1 for sintering products, a return track 2 in parallel with the tunnel furnace 1 and connecting passages 3a and 3b. After removal of sintered products from trolleys 4 used for sintering the products in the tunnel furnace 1 according to a predetermined schedule, the trolleys are transferred to the return track 2 by means a transfer car 5a in the connecting passage 3a. The transferred trolleys 4 are progressively forced into entrance of the return track 2 by means of trolley feeding means 6 so that a predetermined number of the trolleys 4 are gathered together in the return track 2. On the other hand, on an exit side of the return track 2 the trolleys are forced out of the return track 2 into the connecting passage 3b one by one every time when one trolley 4 is forced into the return track 2. The trolley 4 forced into the connecting passage 3b is transferred toward the tunnel furnace 1 by means of a transfer car 5b. The transferred trolleys 4 are progressively forced into an entrance of the tunnel furnace 1 by means of trolley feeding means (not shown). The trolleys in the tunnel furnace 1 and the return track 2 are closely gathered in an end-to-end relation always to keep constant numbers of the trolleys 4 in the furnace and return track, respectively. In the trolley transfer system above described, since the trolleys 4 are gathered and connected from the entrance to the exit of the return track 2, the system encounters the following disadvantages. 1. There is no clearance between the trolleys. Therefore, it is difficult for operators to move through clearances between the trolleys, even if it is not impossible. 2. It is required to provide the trolleys 4 in the return track 2 in the same number as that of the trolleys 4 in the tunnel furnace 1. 3. If a problem occurs in the lower portion of a trolley 4 in the return track 2, it is impossible to repair the troubled portion of the trolley at the location. 4. In the event that some of refractory bricks constituting the trolley are damaged, the damaged trolley often improperly urges the preceding trolley so that refractory bricks of the preceding trolley are damaged and positions of the shelf assembly are shifted. AT-B-162641 discloses, for use in industrial ovens, a conveyor apparatus comprising trolley-like members, each having a single wheel set and a pair of longitudinal bars mounted on the wheel set at one end and connecting to the next trolley-like member at their other end. It is an object of the invention to provide an improved trolley transfer connection for a tunnel furnace, which eliminates the disadvantages of the prior art above described and can transfer trolleys with high efficiency. The invention is set out in claim 1 and in claim 5. According to the invention, the engaging means or protrusions provided at one end of the bar member engage a connecting portion of one of trolleys to be connected and the support bar engages for example a frame of the trolley to support the bar member. Therefore, the unit is first connected to one trolley to support the unit by the trolley and second the trolley is caused to approach the other trolley so that the protrusions on the side of the other trolley engage the connecting portion of the other trolley to connect the two trolleys. When, for example, trolleys in a return track are successively connected in the manner as above described, the trolleys are spaced from each other by predetermined distances to provide spaces between the trolleys. Therefore, operators can pass across a series of the trolleys and the number of the trolleys in the return track can be reduced. Moreover, when a problem occurs in one trolley in the return track, the connections associated with the troubled trolley and adjacent trolleys are removed to enlarge the spaces forward and rearward of the troubled trolley. Therefore, repairing is readily effected at the location. In order that the invention may be more clearly understood, preferred embodiments will be described, by way of example, with reference to the accompanying drawings. Fig. 1 is a schematic view illustrating a trolley transfer system of the prior art for use in a tunnel furnace; Fig. 2 is a schematic view illustrating a condition of trolleys in a return track according to a prior art; Fig. 3 is a perspective view illustrating one embodiment of the trolley transfer connection in one embodiment according to the invention; Fig. 4 is an explanatory view illustrating mounting the unit onto trolleys in the embodiment of Fig.3; and Fig. 5 is a schematic view illustrating mounted units according to the invention on trolleys in a return track. Fig. 3 is a perspective view illustrating one embodiment of the trolley transfer connection unit for a tunnel furnace according to the invention. The connection unit comprises a bar member 11 made of a metal, two pairs of protrusions 12a, 12a', 12b and 12b' provided one pair at each end of the bar member 11 for embracing sides of connecting portions at lower parts of trolleys, and a support bar 13 for horizontally supporting the bar member 11. The bar member 11 suffices to have a strength to resist to urging forces from the trolleys. So long as such requirement for strength is fulfilled, the bar member 11 may be hollow instead of solid cylindrical shape as shown. In this embodiment, the two pairs of protrusions are provided at both the ends of the bar member 11. However, so long as they can maintain the trolleys in a predetermined distance, other constructions may be used. For example, the connecting portions may be formed with apertures into which the protrusions may be adapted to be fitted or only one protrusion may be formed in the bar member to be inserted into an aperture formed in the connecting portion of the trolley. It is only required to engage parts of the two trolleys. The support bar 13 has one end connected to an upper portion of the bar member 11 and extends therefrom toward the other end upwardly at a slight angle. A vertical bar 15 of the support bar 13 has its ends connected to the other end of the support bar 13 and the upper portion of the bar member 11, respectively. A bent portion 16 of the support bar 13 extends from the connecting portion of the support bar 13 and the vertical bar 15 so as to be engaged with or fitted in an aperture 21 of a frame 20 of either of trolleys to be connected. When the protrusions 12b and 12b' embrace the sides of the connecting portion at the lower part of one trolley and the bent portion 16 of the support bar 13 engages with or fitted in the frame of the other trolley, the bar member 11 is maintained horizontally even if the protrusions 12a and 12a' do not embrace the sides of the connecting portion at the lower part of the other trolley. In operation of the unit, therefore, after the unit is connected to one trolley, the unit is also connected to the other trolley by moving the other trolley. Fig. 4 illustrates the connecting operation of the unit to two trolleys. The protrusions 12b and 12b' embrace the sides of the connecting portion (not shown) provided at the lower portion of the rear trolley 17, while the bent portion 16 of the support bar 13 is fitted in the aperture 21 of the frame 20 so that the bar member 11 is maintained horizontally in conjunction with the actions of the protrusions and the bent portion. Thereafter, the rear trolley is pushed forward to approach the preceding trolley 22 so that the protrusions 12a and 12a' engage and embrace the sides 25 of the connecting portion 24 of the preceding trolley. The preceding and rear trolleys 22 and 17 are thus connected with a predetermined distance in this manner. The connecting operation of trolleys in a return track by means of the units is shown in Fig. 5. Reference numeral 26 denotes the trolleys. As can be seen from the above explanation, according to the invention the following advantages are obtained by connecting trolleys with predetermined distances by means of the bar members horizontally supported by support bars, respectively. 1. There are spaces between trolleys in a return truck so that operators can pass across a series of the trolleys. 2. Since the trolleys are arranged with predetermined intervals, the number of trolleys in a return track can be reduced. 3. When a problem occurs in one trolley among the trolleys in the return track, spaces on forward and rearward sides of the troubled trolley can be enlarged by removing the trolley transfer connection units associated with the troubled and adjacent trolleys so that repairing the troubled trolley can be readily carried out at the location.

Claims: Tunnel kiln trolleys (4) for a tunnel furnace (1), each trolley having two wheel sets and a supporting structure for articles carried by the trolley interconnecting the wheel sets, there being coupling means between two trolleys (4) comprising a bar member (11) having at least one engaging means (12) provided on at least one end for engaging one of the trolleys to be connected, and a support bar (13) secured to said bar member (11) and engaged with the other trolley to support said bar member (11). Tunnel kiln trolleys according to claim 1, wherein said engaging means (12) comprises two protrusions (12a,12',12b,12b') at each end of the bar member (11), and the bar member (11) is supported by the support bar (13) engaging said other trolley and the two protrusions (12a, 12a') provided at one end of the bar member and engaging a frame of the other trolley. Tunnel kiln trolleys according to claim 1, wherein said support bar (13) has one end connected to the bar member (11) and extends therefrom toward its other end upwardly at a slight angle, and said support bar (13) further comprises a vertical bar (15) having one end connected to the other end of the bar member (11) and its other end connected to the support bar (13), and a bent portion (16) extending from the connection of the support bar and the vertical bar and having an end to be engaged with said other trolley. Tunnel kiln trolleys according to claim 3, wherein said bent portion (16) has a vertical portion to be received in an aperture (21) of said other trolley. A tunnel furnace (1) having a transfer path (2) for moving tunnel kiln trolleys (4) from end-to-end of said furnace (1) outside said furnace, each trolley having two wheel sets and a supporting structure for articles carried by the trolley interconnecting the wheel sets, wherein in said transfer path (2), two adjacent trolleys (4) are connected at a predetermined spacing by a bar member (11) having at least one engaging means (12) provided on at least one end for engaging one of the trolleys to be connected, and a support bar (13) secured to said bar member (11) and engaged with the other trolley to support said bar member (11).

Inventors: MIYAHARA, KAZUHIRO, 201, NGK MINAMI-KAZOKU, YASUDA, KEIJI
Applicants: NGK INSULATORS, LTD.
Application year: 1989
Main classification: F27B9
IPC codes: F27B9, B60D3