Foldable stroller frame

[0001] This application claims priority of People Republic of China Application No. 201010249667.7, filed on Aug. 2, 2010.

[0002] 1. Field of the Invention

[0003] The invention relates to a foldable stroller frame, particularly to a foldable stroller frame including a leg and a handle connected slidably to the leg.

[0004] 2. Description of the Related Art

[0005] Conventional foldable stroller frames normally include front and rear leg units pivoted to each other, and a handle unit pivoted to the front and rear leg units. In order to permit the stroller frame to be foldable, one of the front and rear leg units and the handle unit is required to be foldable or extra linking units are required to interconnect the front and rear leg units. People Republic of China Patent No. CN1600616 discloses a stroller including a first handle bar, a second handle bar, a first rear leg pivoted to the first handle bar, a second rear leg pivoted to the second handle bar, a first front leg pivoted to the first handle bar, a second front leg pivoted to the second handle bar, and a middle support connected to and disposed among the first and second rear legs and the first and second handle bars. The first front leg and the first rear leg are pivoted to a first linking bar so that the first front leg, the first rear leg, the first handle bar and the first linking bar cooperatively form a first four-bar linkage. The second front leg and the second rear leg are pivoted to a second linkage so that the second front leg, the second rear leg, the second handle bar and the second linking bar cooperatively form a second four-bar linkage. The aforesaid stroller frame is permitted to be foldable through the inclusion of the first and second linking bars, which makes the structure of the stroller frame more complex and results in an increase in the weight of the stroller frame.

[0006] Therefore, an object of the present invention is to provide a stroller frame that has a simple structure and is lighter in weight than the aforesaid conventional stroller frame.

[0007] According to this invention, there is provided a foldable stroller frame that comprises: two opposite foldable side frame units; and a foldable middle support interconnecting the side frame units. Each of the side frame units includes a handle rod, a first leg pivoted to the handle rod and adapted to be connected to a first stroller wheel, a second leg pivoted to the first leg and adapted to be connected to a second stroller wheel, and a connecting slider mounted slidably on the second leg. The handle rod has a lower end portion pivoted to the connecting slider so as to be co-slidable with the connecting slider on the second leg.

[0019] FIGS. 1 to 8 illustrate the preferred embodiment of a foldable stroller frame according to this invention. The foldable stroller frame includes: two opposite foldable side frame units 110; and a foldable middle support 100 interconnecting the side frame units 110. Each of the side frame units 110 includes a handle rod 111, a first leg 121 pivoted to the handle rod 111 and adapted to be connected to a first stroller wheel 121a, a second leg 131 pivoted to the first leg 121 and adapted to be connected to a second stroller wheel 131a, and a connecting slider 161 mounted slidably on the second leg 131. The handle rod 111 has a lower end portion 1112 pivoted to the connecting slider 161 (see FIGS. 1, 2, 8 and 9) so as to be co-slidably with the connecting slider 161 on the second leg 131.

[0020] In this embodiment, the connecting slider 161 has a cylindrical sleeve portion 1611 (see FIGS. 2, 8 and 9) and an ear plate portion 1612 extending outwardly from the sleeve portion 1611. The sleeve portion 1611 is slidably sleeved on the second leg 131.

[0021] Each of the first and second legs 121, 131 has a bottom end 121b, 131b. The bottom ends 121b, 131b of the first and second legs 121, 131 are connected to the first and second stroller wheels 121a, 131a, respectively. The stroller frame is operable between a folded state (see FIG. 10) and an extended state (see FIGS. 1, 2, 3 and 8). The bottom ends 121b, 131b of the first and second legs 121, 131 are moved toward each other when the stroller frame is extended from the folded state (see FIG. 10) to the extended state (see FIG. 8), and are moved away from each other when the stroller frame is folded from the extended state to the folded state.

[0022] The stroller frame of the preferred embodiment further includes a foldable stretching unit 180 and a locking unit 190. The stretching unit 180 is disposed between and is pivoted to the side frame units 110 so as to be co-foldable with the side frame units 110. The side frame units 110 are moved toward each other when the stroller frame is folded from the extended state (see FIGS. 1 and 3) to the folded state (see FIG. 10), and are moved away from each other when the stroller frame is extended from the folded state to the extended state. The locking unit 190 is operable to lock the stretching unit 180 against folding from an extended position (see FIGS. 1, 3 and 4) to a folded position (see FIG. 10), thereby preventing the side frame units 110 from moving toward each other.

[0023] The stretching unit 180 includes a vertical pulling rod 181 having upper and lower end portions 1811, 1812 (see FIGS. 3, 4 and 5), two upper lateral rods 182, and two lower lateral rods 183. A pedal 185 is secured to the lower end portion 1812 of the vertical pulling rod 181. The locking unit 190 includes an upper seat 194, a pulling handle 193 formed on the upper seat 194, a lower seat 192 spaced apart from the upper seat 194, two linking rods 184, and a resiliently biased latch 210. The upper seat 194 is secured to the upper end portion 1811 of the vertical pulling rod 181 through a fastener 195 (see FIGS. 4 and 5). The lower seat 192 is slidably mounted to the vertical pulling rod 181 so as to permit relative movement of the upper and lower seats 194, 192. The upper lateral rods 182 are pivoted to the handle rods 111 of the side frame units 110 and two opposite sides of the upper seat 194, respectively (see FIG. 3). The lower lateral rods 183 are pivoted to the handle rods 111 of the side frame units 110, respectively, and to the lower end portion 1812 of the vertical pulling rod 181 (see FIGS. 3 and 4). The linking rods 184 have lower ends pivoted to the handle rods 111 of the side frame units 110, respectively, and upper ends pivoted to the lower seat 192 (see FIGS. 3 and 4) so as to form an inverted V-shaped configuration.

[0024] The latch 210 is attached to one of the upper and lower seats 194, 192, and engages releasably the other of the upper and lower seats 194, 192 so as to prevent the upper and lower seats 194, 192 from moving away from each other and the linking rods 184 from changing in configuration, thereby preventing folding of the stroller frame. In this embodiment, the latch 210 is attached to the upper seat 194, and engages the lower seat 192. It is noted that in order to fold the stroller frame, the lower ends of the linking rods 184 are required to be able to move toward each other (see FIG. 10). Hence, when the latch 210 engages the lower seat 192, the lower seat 192 is inhibited to move along the vertical pulling rod 181 (see FIG. 3), which prevents the linking rods 184 from rotating toward each other.

[0025] The upper seat 194 is formed with an upper recess 194a (see FIG. 5). The latch 210 has upper and lower portions 2101, 2102 (see FIGS. 5 and 6). The upper portion 2101 of the latch 210 extends into the upper recess 194a, and is formed with pivot studs 210a (see FIG. 6) pivoted to the upper seat 194 so as to permit the latch 210 to be rotatable relative to the upper seat 194 between a locking position (see FIG. 5) and a releasing position (not shown). The upper and lower portions 2101, 2102 cooperatively defining an engaging recess 213 (see FIGS. 5 and 6). The lower seat 192 is formed with a lower recess 192a and an engaging protrusion 192b protruding therefrom into the lower recess 192a. The lower portion 2102 of the latch 210 extends into the lower recess 192a and the engaging protrusion 192b engages releasably the engaging recess 213 (see FIG. 5) when the latch 210 is disposed at the locking position. The lower portion 2102 of the latch 210 is disposed outside of the lower recess 192a and the engaging protrusion 192b is disengaged from the engaging recess 213 when the latch 210 is disposed at the releasing position (not shown).

[0026] The upper portion 2101 of the latch 210 is further formed with a resilient arm 212 extending into the upper recess 194a (see FIG. 5) and abutting resiliently against the upper seat 194 so that when the upper portion 2101 of the latch 210 is pressed to rotate the latch 210 from the locking position to the releasing position, the resilient arm 212 can accumulate a restoring force to restore the latch 210 from the releasing position to the locking position.

[0027] The middle support 100 includes two crossing rods 101, 102 pivoted to and crossing each other. Each of the crossing rods 101, 102 is pivoted to the handle rod 111 of one of the side frame units 110 and to the first leg 121 of the other of the side frame units 110.

[0028] The stroller frame of the preferred embodiment further includes a foldable backrest assembly 140 connected to second legs 131 of the side frame units 110 (see FIGS. 1 to 3). The backrest assembly 140 includes two vertical beams 141, two crossing beams 142, and two interconnecting beams 143. The vertical beams 141 are pivoted to the second legs 131 of the side frame units 110, respectively. The crossing beams 142 are pivoted to and cross each other, and are further pivoted to the vertical beams 141, respectively. Each of the interconnecting beams 143 is pivoted to a respective one of the vertical beams 141 and a respective one of the crossing beams 142.

[0029] Each of the side frame units 110 further includes an ear plate 171 (see FIGS. 1 and 2) secured to the handle rod 111. The first leg 121 has an upper end 1213 pivoted to the ear plate 171.

[0030] In a folding operation, the upper portion 2101 of the latch 210 is pressed to release engagement between the latch 210 and the lower seat 192, followed by pulling upward the vertical pulling rod 181 and moving forward the handle rods 111 toward the first legs 121 to fold the stroller frame (see FIG. 9). The upward pulling action of the vertical pulling rod 181 results in upward movement of the upper seat 194 and the vertical pulling rod 181 relative to the lower seat 192 and the linking rods 184 and in folding of the upper lateral rods 182, the lower lateral rods 183, the linking rods 184, the crossing rods 101, 102 and the side frame units 110 toward each other. The forward moving action of the handle rods 111 results in movement of the handle rods 111 and the first legs 121 toward each other and overlapping of the handle rods 111 and the first and second legs 121, 131 (see FIG. 10).

[0031] In an extending operation, the handle rods 111 of the side frames 110 are lifted to move away from the first legs 121 by the stroller operator's hand and the pedal 185 is pressed downward by the stroller operator's foot to cause pivotal extension of the upper lateral rods 182, the lower lateral rods 183, and the linking rods 184, which, in turn, results in pivotal extension of the crossing rods 101, 102 and the side frame units 110 until the stroller frame is fully extended.

[0032] With the use of the connecting sleeves 161 on the second legs 131 to connect slidably the handle rods 111 to the second legs 131, the stroller frame of the present invention can be foldable without forming a four-bar linkage structure, and the arrangement as such can improve the aforesaid drawbacks associated with the prior art. In addition, lifting of the handle rods 111 of the side frames 110 away from the first legs 121 from a folded state, or a lower position, to extend the stroller frame is convenient and easy for the stroller operator.

[0033] While the present invention has been described in connection with what are considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation 50 as to encompass all such modifications and equivalent arrangements.