Regulation 3.2(2) AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION INNOVATION PATENT Application Number: Lodged: Invention Title: Stroller that can be folded and expanded easily and quickly The following statement is a full description of this invention, including the best method of performing it known to us: STROLLER THAT CAN BE FOLDED AND EXPANDED EASILY AND QUICKLY The present innovation relates to a stroller and, more particularly, to a baby stroller for placing a baby. 5 A conventional stroller comprises a frame that is folded by a gearing mechanism. However, the gearing mechanism is easily worn out during a long-term utilization. In addition, the stroller has a larger volume and cannot be folded easily and conveniently by operation of the gearing mechanism. In accordance with the present innovation, there is provided a stroller, 10 comprising a front wheel frame, a rear wheel frame pivotally connected with the front wheel frame, and a main frame connected with the rear wheel frame to move in concert with the rear wheel frame and releasably locked onto the front wheel frame. The front wheel frame includes a front support bar having two opposite support portions, and two locking members mounted on the 15 support portions of the front support bar respectively. The main frame includes two extension tubes each pivotally connected with the rear wheel frame, two movable members movably mounted on the extension tubes respectively and detachably locked onto the locking members of the front wheel frame respectively, two drive knobs movably mounted on the extension tubes 20 respectively, and two drive cords movably mounted in the extension tubes respectively and each having a first end attached to a respective one of the movable members to move the respective movable member and a second end attached to and driven by a respective one of the drive knobs. The primary objective of the present innovation is to provide a stroller that can be folded and expanded easily and quickly. 5 Another objective of the present innovation is to provide a stroller, wherein a user only needs to pull the drive knobs of the main frame so as to stroller so that the stroller is folded easily and quickly, thereby facilitating the user folding the stroller. A further objective of the present innovation is to provide a stroller, 10 wherein when the stroller is folded, the front wheel frame, the rear wheel frame and the main frame are juxtaposed to and parallel with each other so that the stroller has a smaller volume when being folded. A further objective of the present innovation is to provide a stroller that can provide two seats by provision of the seat frame. 15 Further benefits and advantages of the present innovation will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings. In the drawings: Fig. 1 is a perspective view of a stroller in accordance with the 20 preferred embodiment of the present innovation. Fig. 2 is a partially exploded perspective view of the stroller as shown in Fig. 1. 2 Fig. 3 is a partially exploded perspective view of the stroller as shown in Fig. 1. Fig. 4 is a partially side cross-sectional view of the stroller as shown in Fig. 1. 5 Fig. 5 is a schematic operational view of the stroller as shown in Fig. 4. Fig. 6 is a schematic operational view of the stroller as shown in Fig. 5. Fig. 7 is a schematic operational view of the stroller as shown in Fig. 10 6. Fig. 8 is a perspective view of a stroller in accordance with another preferred embodiment of the present innovation. Fig. 9 is a perspective view of the stroller in accordance with another preferred embodiment of the present innovation. 15 Fig. 10 is a perspective view of the stroller in accordance with another preferred embodiment of the present innovation. Referring to the drawings and initially to Figs. 1-4, a stroller in accordance with the preferred embodiment of the present innovation comprises d front wheel frame 3, a rear wheel frame 2 pivotally connected with 20 the front wheel frame 3, a main frame 1 connected with the rear wheel frame 2 to move in concert with the rear wheel frame 2 and releasably locked onto the 3 front wheel frame 3, an armrest 4 detachably mounted on the rear wheel frame 2, and a seat frame 5 detachably mounted on the rear wheel frame 2. The front wheel frame 3 includes a front support bar 30 having two opposite support portions 32 and two locking members 31 mounted on the 5 support portions 32 of the front support bar 30 respectively. The front support bar 30 of the front wheel frame 3 has a substantially U-shaped profile. Each of the locking members 31 of the front wheel frame 3 has a side provided with at least one locking hook 33. The main frame 1 includes two extension tubes 11 each pivotally 10 connected with the rear wheel frame 2, two movable members 14 movably mounted on the extension tubes 11 respectively and detachably locked onto the locking members 31 of the front wheel frame 3 respectively, two drive knobs 12 movably mounted on the extension tubes 11 respectively, two drive cords 16 movably mounted in the extension tubes 11 respectively and each having a 15 first end 160 attached to a respective one of the movable members 14 to move the respective movable member 14 and a second end 162 attached to and driven by a respective one of the drive knobs 12, two retaining members 15 mounted on the extension tubes 11 respectively, two elastic 'members 17 mounted in the extension tubes 11 respectively and each biased between a 20 respective one of the movable members 14 and a respective one of the retaining members 15 to pull the respective movable member 14 toward the respective locking member 31 of the front wheel frame 3, and two stop 4 members 13 mounted on the extension tubes 11 respectively to stop movement of the movable members 14 respectively when the movable members 14 are detached from the locking members 31 of the front wheel frame 3 respectively. The main frame 1 further includes two locking pins 140 extending 5 through the movable members 14 respectively and through the extension tubes 11 respectively to attach the movable members 14 to the extension tubes 11 respectively, and two guiding pins 120 extending through the drive knobs 12 respectively and through the extension tubes 11 respectively to attach the drive knobs 12 to the extension tubes 11 respectively. 10 Each of the extension tubes 11 of the main frame 1 has an upper end provided with an elongate sliding slot 111 and a lower end provided with an elongate guiding slot 112. Each of the locking pins 140 of the main frame 1 is slidable in the guiding slot 112 of the respective extension tube 11. Each of the locking pins 140 of the main frame 1 is detachably locked onto the locking 15 hook 33 of the respective locking member 31. Each of the guiding pins 120 of the main frame 1 is slidable in the sliding slot 111 of the respective extension tube 11. Each of the elastic members 17 of the main frame 1 has a first end 170 secured to a respective one of the locking pins 140 and a second end 172 secured to the respective retaining member 15. The first end 160 of each of the 20 drive cords 16 is secured to a respective one of the locking pins 140 to move the respective locking pin 140, and the second end 162 of each of the drive cords 16 is secured to a respective one of the guiding pins 120 to move in 5 concert with the respective guiding pin 120. Each of the stop members 13 of the main frame 1 has an end portion provided with a receiving groove 131 to allow insertion of a respective one of the movable members 14 when the respective movable member 14 is detached from the respective locking 5 member. The rear wheel frame 2 includes two pivot brackets 21 each pivotally mounted on a respective one of the support portions 32 of the front support bar 30, two support tubes 20 each having an upper end fixed on a respective one of the pivot brackets 21, two mounting brackets 23 each mounted on a lower end 10 of a respective one of the support tubes 20, and two connecting brackets 22 each pivotally mounted on a respective one of the pivot brackets 21 and each fixed on a respective one of the extension tubes 11 of the main frame 1. Each of the mounting brackets 23 of the rear wheel frame 2 has a side provided with a mounting hole 231. Each of the connecting brackets 22 of the rear wheel frame 15 2 has a side provided with a mounting sleeve 221. The armrest 4 is detachably mounted between the connecting brackets 22 of the rear wheel frame 2. The armrest 4 has two opposite ends each provided with a plug 40 adjustably mounted in the mounting sleeve 221 of the respective connecting bracket 22 by an elastic plate 41. 20 The seat frame 5 is detachably mounted between the mounting brackets 23 of the rear wheel frame 2. Alternatively, the seat frame 5 is detachably mounted between the connecting brackets 22 of the rear wheel 6 frame 2. The seat frame 5 has two opposite ends each provided with a post 50 adjustably mounted in the mounting hole 231 of the respective mounting bracket 23 or in the mounting sleeve 221 of the respective connecting bracket 22 by an elastic plate 51. 5 In operation, referring to Figs. 4-7 with reference to Figs. 1-3, each of the locking pins 140 of the main frame 1 is locked onto the locking hook 33 of the respective locking member 31.by the elastic force of the respective elastic member 17 as shown in Fig. 4 so that each of the movable members 14 is locked onto the respective locking member 31 of the front wheel frame 3 at a 10 normal state. When the drive knobs 12 of the main frame 1 are pulled upward, the drive cords 16 are pulled upward so that each of the locking pins 140 of the main frame 1 is moved upward to detach from the locking hook 33 of the respective locking member 31, and each of the movable members 14 is moved upward to detach from the respective locking member 31 of the front wheel 15 frame 3 as shown in Fig. 5, so as to unlock the extension tubes 11 of the main frame 1 from the support portions 32 of the front support bar 30. In such a manner, each of the pivot brackets 21 is pivoted about the respective support portion 32 of the front support bar 30 so that each of the extension tubes 11 of the main frame 1 and each of the support tubes 20 of the rear wheel frame 2 are 20 pivoted relative to the respective support portion 32 of the front support bar 30 as shown in Fig. 6. After each of the support tubes 20 of the rear wheel frame 2 is moved to abut the respective support portion 32 of the front support bar 30, 7 each of the connecting brackets 22 is pivoted about the respective pivot bracket 21 so that each of the extension tubes 11 of the main frame 1 is pivoted relative to the respective support tube 20 of the rear wheel frame 2 until each of the extension tubes 11 of the main frame 1 is moved to abut the respective support 5 tube 20 of the rear wheel frame 2 as shown in Fig. 7 so as to fold the stroller. As shown in Fig. 8, the armrest 4 is detachably mounted between the connecting brackets 22 of the rear wheel frame 2, the seat frame 5 is detachably mounted between the mounting brackets 23 of the rear wheel frame 2, and the stroller further comprises a first seat 6 mounted on the main frame 1 and the 10 front wheel frame 3 and limited by the armrest 4, and a second seat 60 mounted on and supported by the seat frame 5. As shown in Figs. 9 and 10, the seat frame 5 is detachably mounted between the connecting brackets 22 of the rear wheel frame 2, and the stroller further comprises a seat 62 mounted on the main frame 1 and the front wheel 15 frame 3 and limited by the seat frame 5. Accordingly, a user only needs to pull the drive knobs 12 of the main frame 1 so as to stroller so that the stroller is folded easily and quickly, thereby facilitating the user folding the stroller. In addition, when the stroller is folded, the front wheel frame 3, the rear wheel frame 2 and the main frame I are 20 juxtaposed to and parallel with each other as shown in Fig. 7 so that the stroller has a smaller volume when being folded. Further, the stroller can provide two seats by provision of the seat frame 5. 8 The terms "comprise(s)" and "comprising" as used in the specification and claims mean "consisting at least in part of', that is to say when interpreting statements in the specification and claims which include any of those terms, the features, prefaced by any of those terms in each statement, 5 all need to be present but other features can also be present. Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. 10 Although the innovation has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present innovation. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall 15 within the true scope of the innovation. 9