FRAME-OPENING AND CLOSING MECHANISM PROVIDED WITH A TORSION BAR

Abstract: A frame connection member (18) which is fixedly mounted on one of said upper frame part (2A) or lower frame part (2B) is pivotably hinged to the other frame part (2A or 2B) for rotary motion around a horizontal axis shaft line (P). An inversely tapered concavity (c) is formed in said frame connection member (18) for inserting a twisted shaft portion (b) of said torsion bar (16) from a direction meeting at right angles with the axis shaft line (P) of the twisted shaft portion (b). Said frame connection member (18) is provided with a first engagement member (21) for engaging an energizing reaction froce portion (f) on one end side of said torsion bar(16), said other frame part (2A or 2B) is provided with a second engagement member (23) for engaging an energizing reaction force portion (ℓ) on the other end side of said torsion bar (16). Said other frame part (2A or 2B) is provided with a rotation limiting member (22) for regulating the angle of rotation of said frame connection member (18) relative to said other frame part (2A or 2B) within a range larger than the opening angle allowed by an open position regulating means (19). The setting of the torsion bar (16) can be very simply and easily achieved by merely inserting said twisted shaft portion (b) of the torsion bar (16) into the inversely tapered concavity (c) sideways and slightly twisting said twisted shaft portion (b).

Description: The present invention relates to a frame-opening and closing mechanism provided with a torsion bar in a clamshell type image-forming apparatus such as an electrostatic photographic copying machine, a facsimile apparatus and the like, in particular to a frame-opening and closing mechanism provided with a torsion bar comprising an upper frame part connected with a lower frame part so as to be hinged for opening and closing around a horizontal axis shaft line, a torsion bar provided on a connection structure for energizing said upper frame part in an opening direction, and an open position regulating means for regulating said upper frame part at an appointed open angle. In order to energize the upper frame part in the open direction in the above described frame-opening and closing mechanism, a connection member 32 is connected with both sides in a back and forth direction (a direction meeting at right angles with a paper surface in Fig. 13) of an upper frame part 31. A frame connection member 34 which is connected with a lower frame part 33 is pivotably supported on said connection member 32 through a cylindrical connection means 35. Two cranklike torsion bars 36 both provided with bent ends are inserted into said cylindrical connection means 35. A twisted shaft portion s of said torsion bar 36 twisted to clamp one energizing reaction force portion t of said torsion bar 36 on said frame connection member 34 and the other energizing reaction force portion u on said connection member 32, respectively. Thereby giving an energizing force in the open direction to said upper frame part 31, as disclosed for example in the nearest prior art Japanese Utility Model Laid-Open No. Sho 62-82670 and shown also in Figs. 13 and 14. However, since said energizing reaction force portions t, u of the above described torsion bars 36 are bent, the disadvantages have occurred in that it is remarkably difficult to insert said torsion bars 36 into said cylindrical connection means 35 and it is required to supply a sufficient energizing force in the opening direction to said frame part 31 under the open position regulated condition of said upper frame part 31. Therefore a rotation limiting member 37 is engaged with an open position regulating member 38 so that the twisted shaft portion s of said torsion bar 36 is greatly twisted to move said both members 32, 24, thereby requiring much work. The present invention has been achieved in view of the above described actual state. Thus, it is an object of the present invention to provide a frame-opening and closing mechanism capable of easily clamping said torsion bar without increasing the number of constituent parts of the frame-opening and closing mechanism which is remarkably improved. In order to achieve the above described object, there is defined in Claim 1 a frame-opening and closing mechanism provided with a torsion bar according to the present invention comprises an upper frame part connected with a lower frame part so as to be hinged for opening and closing around a horizontal axis shaft line, a torsion bar provided on a connection structure for energizing said upper frame part in an opening direction, and an open position regulating means for regulating said upper frame part at an appointed open angle and is characterized by that a frame connection member fixedly mounted on one of said upper frame part or lower frame part is pivoted on the other frame part for rotary motion around said horizontal axis shaft line, an inversely tapered concavity formed in said frame connection member for inserting a twisted shaft portion of said torsion bar from a direction meeting at right angles with the axis shaft line of the twisted shaft portion said frame connection member is provided with a first engagement member as an abutment for a first reaction force portion on one end side of said torsion bar, said other frame part is provided with a second engagement member as an abutment for a second reaction force portion on the other end side of said torsion bar, and said other frame part is provided with a reaction limiting member for regulating the angle of reaction of said frame connection member relative to said other frame part within a range larger than the opening angle, allowed by said open position regulating means. According to the above described characteristic construction, the setting of the torsion bar giving the energizing force to said upper frame in the opening direction can be achieved by inserting the torsion bar into the inversely tapered concavity formed in said frame connection member under the condition that said frame connection member is pivotably hinged on said other frame part and engaging both end energizing reaction force portions of said torsion bar with the first and second engagement members. Further, upon connecting said frame connection member with said one frame part, rotating said other frame part in the closing direction until the appointed opening angle or less, and providing the open position regulating means, the installation of the upper frame part which is regulated at the appointed opening angle relatively to said lower frame part is completed. Preferred embodiments of the invention as defined in the dependent claims 2 to 5 will be described in the following with reference to the accompanying drawing, wherein: Fig. 1 is a perspective view showing a frame-opening and closing mechanism provided with torsion bars; Fig. 2 is a rough longitudinal sectional view showing an electrostatic photographic copying machine which is one example of objects to which the frame-opening and closing mechanism is applied; Fig. 3 is a longitudinal section view showing an opened condition of an upper frame part; Fig. 4 is a detail perspective view showing a connection structure; Fig. 5 is a side view showing a condition that the frame-opening and closing mechanism is set on the upper frame part; Fig. 6 is a side view showing a condition that the angle of rotation of a frame connection member is regulated. Fig. 7 is a side view showing a condition that an opening angle of the upper frame part is regulated; and Fig. 8 is a side view showing a completely closed condition of the upper frame part. Another preferred embodiment of the frame-opening and closing mechanism provided with torsion bars is shown in Figs. 9 to 11, in which Fig. 9 is a detail perspective view; Fig. 10 is a side view showing a condition that the angle of rotation of the frame connecntion member is regulated; and Fig. 11 is a side view showing a condition that the opening angle of the upper frame part is regulated; Fig. 12 is a front view showing a torsion bar acording to another preferred embodiment. And Figs. 13, 14 are side views showing the conventional example of the frame-opening and closing mechanism provided with torsion bars, respectively, in which Fig. 13 is a side view and Fig. 14 is a perspective view. The preferred embodiments of the present invention are described below with reference to the drawings. Fig. 1 is a detail drawing showing a frame-opening and closing aparaturs A. Figs. 2, 3 are schematic drawings showing a so-challed clamshell type electrostatic photographic copying machine as a whole. In this copying machine a photoreceptor 3 is beared in a frame 2 of the copying machine provided with a manuscript table 1 which is reciprocatable in a paper supply direction. An electrifying apparatus 4, a developing apparatus 5, a transferring apparatus 6, a paper-separating apparatus 7 and a cleaning apparatus 8 are disposed around said photoreceptor 3 in this order. An exposure apparatus 9 is disposed in a space above said cleaning apparatus 8. Additionally, a paper-conveying apparatus 11 for conveying papers housed in a cassette case 10 to said transferring apparatus 6, a discharged paper-conveying apparatus 13 for conveying separated papers to a fixation apparatus 12 and a pair of paper-discharging rollers 15 for discharging fixed papers to a tray 14 are provided. The frame 2 of the copying machine is divided into two parts, that is, an upper frame part 2A and a lower frame part 2B, with a paper supply course as a border. The frame-opening and closing apparatus A is provided to extend over said both frame parts 2A, 2B on the upstream side in the paper supply direction so that the upper frame part 2A provided with said photoreceptor 3, said exposure apparatus 9 and the like may be rotated, opened and closed around a horizontal axis shaft line P under the condition that a locking mechanism (not shown) disposed on a downstream side in the paper supply direction is released. Said frame-opening and closing apparatus A is provided with two sets of connection structures B symmetric in construction to each other on both sides of a horizontal direction meeting at right angles with the paper supply direction relative to said frame 2 of the copying machine, in other words, in the back and forth direction of the frame 2 of the copying machine, in short, a direction of an axis shaft line of said horizontal axis shaft line P. Two pieces of torsion bars 16 are extending over said two sets of connection structures B. In particular, as shown also in Fig. 4, a connection shaft 17 having a threaded hole a at an end portion thereof is provided on said upper frame part 2A so that the axis shaft line of said connection shaft 17 may be coaxial with said horizontal axis shaft line P. An inversely tapered concavity c is formed in a frame connection member 18 for inserting a twisted shaft portion b of said torsion bar 16 from a direction meeting at right angles with an axis shaft line Q of said shaft portion b. Said frame connection member 18 is connected with said lower frame part 2B by fastening means. Said frame connection member 18 and an open position regulating means 19 having an open position regulating portion d is rotatably hinged on said connection shaft 17, respectively. A member 20 for preventing said open position regulating means 19 and said frame connection member 18 from coming out is fixedly mounted on said upper frame part 2A and said connection shaft 17 by fastening means, e.g. screws e. A first engagement member 21 for engaging one energizing reaction force portion f of said torsion bar 16, a concave portion i engaged with a connecting projection g and a projection j engaged with a concave portion h of said lower frame part 2B and a portion k to be regulated in revolution by a rotation limiting member 22, which will be mentioned later, are formed in said frame connection member 18. Whereas a second engagement member 23 for enganging the other energizing reaction force portion of said torsion bar 16 and said rotation limiting member 22 for said portion k to be regulated in revolution are formed in said member 20. The portion k to be regulated in revolution of the above described frame connection member 18 is energizely brought into contact with said rotation limiting member 22 when the twisted shaft portion b of said torsion bar 16 is twisted. Therefore, said upper frame part 2A may be slightly energized in the opening direction and the energizing reaction force portions f, of said torsion bar 16 are engaged with said first engagement member 21 and second said engagement member 23, and said open position regulating means 19 is rotatable under the above described condition (refer to Fig. 1). Next, a procedure for connecting the upper frame part 2A with the lower frame part 2B is described. At first, as shown in Figs. 1, 4, 5, the frame connection member 18 and the open position regulating means 19 are held on said connection shaft 17 in an engaged manner and the member 20 is fixedly mounted on said upper frame part 2A to install two sets of connection structures B on said upper frame part 2A. The twisted shaft portion b of the first torsion bar 16 is inserted into the inversely tapered concavities c of both frame connection members 18. Said twisted shaft portion b of said torsion bar 16 is slightly twisted so as to give the energizing force to said upper frame part 2A in the opened direction to engage one energizing reaction force portion f with said first engagement member 21 and the other energizing reaction force portion ℓ with said second engagement member 23. When the energizing reaction force portions f,ℓ are engaged with the first and second engagement members 21, 23 under the condition that said twisted shaft portion b is slightly twisted, the twisted shaft portion b adjacent to said one energizing reactionforce portion f is engaged with a lower concave portion of said inversely tapered concavity c in an energized manner. The shaft portion b adjacent to said other energizing reaction force portion ℓ is engaged with an upper concave portion of said inversely tapered concavity c by the reaction force acting upon said twisted shaft portion b. Thereby said torsion bar 16 can be prevented from coming out of the above described inversely tapered concavity c. On the other hand, the angle of rotation of said frame connection member 18 relative to said upper frame part 2A is limited by bringing the portion k to be regulated in revolution of said frame connection member 18 into contact with the rotation limiting member 22 of the member 20 in an energized manner. The above described similarly holds good also for the second torsion bar 16. That is to say said torsion bars 16 can be surely prevented from coming out by the setting operating itself thereof in spite of the remarkably easy setting thereof on said first and second engagement members 21, 23. Thus, the angle of rotation of the frame connection member 18 is regulated against the reaction force of said torsion bar 16 to integrate said frame connection member 18 in the upper frame part 2A. Then, as shown in Fig. 6, the concave portion i and the projection j of said frame connection member 18 are engaged with the connecting projection g and the concave portion h of said lower frame part 2B, respectively. Said frame connection member 18 is fixedly mounted on the lower frame part 2B by fastening means, e.g. screws m. Under this fixedly mounted condition, the opening of the inversely tapered convabity c of said frame-connection member 18 is closed by means of the closing member 2b connected with the lower frame part 2B. Subsequently, as shown in Fig. 7, said upper frame part 2A is closed until an appointed opening angle and said open position regulating means 19 is rotated to bring the open position regulating portion d into contact with said rotation limiting member 22. A screw r is screwed in a threaded hole q of the frame connection member 18 corresponding to a notch n of said open position regulating means 19. Thereby an opening angle of said upper frame part 2A is regulated at the above described appointed opening angle. Fig. 8 shows the completely closed condition of said upper frame part 2A. In short, the connection structures B are mounted on both sides of said upper frame part 2A and then the torsion bars 16 are set through said inversely tapered concavity c under the condition that the energizing force is slightly given. Subsequently, the frame connection member 18 is connected with said lower frame part 2B and the open angle of said upper frame part 2A is regulated at the appointed value. Next, another preferred embodiment of the frame-opening and closing mechanism A is shown in Figs. 9 to 11. This preferred embodiment is different in construction from the above described preferred embodiment in the following points. In contrast to the construction in the above described preferred embodiment that the rotation limiting member 22, with which said portion k to be regulated in revolution and portion d to be regulated in the angle of rotation are brought into contact, and the second engagement member 23 for engaging the other energizing reaction force portion ℓ of said torsion bar 16 are formed integrally with said member 20, in this other preferred embodiment the second engagement member 23′ itself is provided in the upper frame part 2A. Further, a threaded pin construction is the rotation limiting member 22′ with which the portion k to be regulated in revolution of the frame connection member 18 is brought into contact when the twisted shaft portion b of the torsion bar 16 is slightly twisted to engage the first and second engagement members 21, 23. The rotation limiting member 22′ is screwed in said upper frame part 2A (refer to Fig. 10). The rotation limiting member 22′ having said threaded pin construction becomes unnecessary under the condition that this opening angle is regulated, and therefore is drawn out when said upper frame part 2A is regulated at the appointed opening angle and is screwed into another hole of said upper frame part 2A as the open position regulating means 19′ (refer to Fig. 11). That is to say, a special feature consists in that said rotation limiting member 22′ is adapted to be used also as the open position regulating means 19′. Next, another preferred embodiment of the torsion bar 16 for energizing said upper frame part 2B in the opened direction is shown in Fig. 12. In this case, a bent portion 24 eccentric in the direction meeting at right angles with the axis shaft line of the twisted shaft portion b of the torsion bar 16 is formed in said twisted shaft portion b. The upper frame part 2A is connected with the lower frame part 2B so as to be hinged for opening and closing around the horizontal axis shaft line P. The eccentric direction of the bent portion 24 is set so that the bent portions 24 of two torsion bars 16 may be exxentrically positioned in the direction of departing from said horizontal axis shaft line P under the condition that said two torsion bars 16 are set over both frame parts 2A, 2B. That is to say, since the movement is hardly brought about in the vicinity of the frame connecting portion 18 of said both frame parts 2A, 2B, in short, around said horizontal axis shaft line P, even during the opening and closing operation of the upper frame part 2A the switches and similars, such as a paper supply switch or a paper-discharging switch, are suitably disposed around said horizontal axis shaft line P. However, if the twisted shaft portion b of the torsion bar 16 is arranged in the vicinity of said horizontal axis shaft line P and said twisted shaft portion b has a linear form, as shown in Fig. 1, the twisted shaft portion b stands in the way, so that said switches are similars cannot but being installed apart from said horizontal axis shaft line P. In view of the above described matter, said switches and similars can be suitably disposed around said horizontal axis shaft line P by forming the bent portion 24 in the twisted shaft portion b of said torsion bar 16 and keeping said bent portion 24 apart from the horizontal axis shaft line P under the condition that said torsion bar 16 is set to form a space 25 shown by a broken line in Fig. 12. In addition, although said connection structures B are provided in the upper frame part 2A and the frame connection member 18 of said connection structures B is connected with the lower frame part 2B in the above described respective preferred embodiments, a construction in which said connection structures B are provided in the lower frame part 2B and the frame connection member 18 of said connection structures B is connected with the upper frame part 2A, may be used. Furthermore, the frame-opening and closing mechanism A having the above described construction can be applied to image-forming apparatus, such as facsimile apparatus and printers, and other various kinds of frame-opening and closing structures in addition to an electrostatic photographic copying machine. As above described, with the frame-opening and closing mechanism provided with a torsion bar according to the present invention, the setting of the torsion bar giving the energizing force to said upper frame part in the opening direction is achieved by inserting the torsion bar into the inversely tapered concavity formed in said frame connection member under the condition that said frame connection member is pivotably hinged on said other frame part and engaging both end energizing reaction force portions of said torsion bar with the first and second engagement members under the condition that the twisted shaft portion of said torsion bar is slightly twisted. That is to say, the setting of the torsion bar can be very simply and easily achieved by merely inserting said twisted shaft portion of the torsion bar into the inversely tapered concavity sideways and slightly twisting said twisted shaft portion. Then, the opening angle of said upper frame can be regulated at the appointed value by connecting said frame connection member with said one frame part rotating said other frame part in the closing direction until the appointed open angle or less, and providing the open position regulating means. Thereby rationally eleminating the conventional disadvantages in spite of the simple improvement as a whole.

Claims: 1. A frame-opening and closing mechanism (A) provided with a torsion bar (16) comprising an upper frame part (2A) connected with a lower frame part (2B) so as to be hinged for opening and closing around a horizontal axis shaft line (P), a torsion bar (16) provided on a connection structure (B) for energizing said upper frame part (2A) in an opening direction, and an open position regulating means (19) for regulating said upper frame part (2A) at an appointed open angle, characterized in that a frame connection member (18) is fixedly mounted on one of said upper or lower frame part (2A or 2B) for rotary motion around said horizontal axis shaft line (P), an inversely tapered concavity (c) is formed in said frame connection member (18) for inserting a twisted shaft portion (b) of said torsion bar (16) from a direction meeting at right angles with the axis shaft line (Q) of the twisted shaft portion (b), said frame connection member (18) is provided with a first engagement member (21) as an abutment for a first reaction force portion (f) on one end of said torsion bar (16), said other frame part (2A or 2B) being provided with a second engagement member (23) as abutment for a second reaction force portion (1) on the other end of said torsion bar ( 16) and said other frame part (2A or 2B) is provided with a rotation limiting member (22) for regulating the angle of rotation of said frame connection member (18) relative to said other frame part (2A or 2B) within a range larger than the opening angle allowed by said open position regulating means (19). 2. The frame-opening and closing mechanism (A) as set forth in claim 1, in which a closing member (2b) is connected with said one frame part (2A or 2B) for closing engagement with the opening of the inversely tapered concavity (c) of said frame connection member (18). 3. A frame-opening and closing mechanism (A) provided with a torsion bar (16) as set forth in claim 1, in which said open position regulating means (19) is pivotably hinged to said other frame part (2A or 2B) for rotary motion around said horizontal axis shaft line (P) and is fixedly mounted on said frame connection member (18) so that said open position regulating means (19) could engage said rotation limiting member (22) under the condition that said upper frame part (2A) is opened by the appointed angle. 4. A frame-opening and closing mechanism (A) provided with a torsion bar (16) as set forth in claim 1, in which a second engagement member (23′) is fixedly mounted on said upper frame part (2A) and an open position regulating means (19′) and a rotation limiting member (22′) are formed by a single threated pin which is selectively screwable into different holes within said upper frame part (2A) for changing the range of angle of rotation of said upper frame part (2A) with respect to the lower frame part (2B). 5. A frame-opening and closing mechanism (A) provided with a torsion bar (16) as set forth in claim 1, in which a bent portion (24) eccentric in the direction of departing from said horizontal axis shaft line (P) is formed in the twisted shaft portion (b) of said torsion bar (16).

Inventors: KOMAKI, SUSUMU
Applicants: MITA INDUSTRIAL CO. LTD.
Application year: 1988
Main classification: E05F1
IPC codes: E05D11, E05F1, G03G21