Title:
Adjustable seat frame
Kind Code:
A1


Abstract:
The invention relates to a seat frame for fitting to the running gear (15) of a wheelchair or pushchair, comprising a backrest (1), a seating surface (2) and feet support (3). The aim of the invention is to produce a seat frame which is particularly flexible and may be adjusted to various sizes. Said aim is achieved, whereby long recesses, in particular grooves (5), are arranged running longitudinally along both sides of the seating surface (2), for housing fixing elements. Preferably, long recesses, in particular grooves (5), are also arranged running longitudinally along both sides of the backrest (1), for housing fixing elements.



Inventors:
Markwald, Michael (Eitorf, DE)
Application Number:
10/468575
Publication Date:
04/29/2004
Filing Date:
12/08/2003
Assignee:
MARKWALD MICHAEL
Primary Class:
International Classes:
A61G5/12; A61G5/10; (IPC1-7): A47C1/02
View Patent Images:
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Primary Examiner:
NELSON JR, MILTON
Attorney, Agent or Firm:
MUIRHEAD AND SATURNELLI, LLC (WESTBOROUGH, MA, US)
Claims:
1. A seat shell which is provided in particular for attachment to the chassis (15) of a wheelchair or a stroller, having a backrest (1), a seat (2), and a footrest (3), characterized in that oblong recesses running in its longitudinal direction, grooves (5) in particular, for receiving fastening elements are situated on both sides of the seat (2).

2. The seat shell as recited in claim 1, characterized in that oblong recesses running in its longitudinal direction, grooves (5) in particular, for receiving fastening elements are situated on both sides of the backrest (1).

3. The seat shell as recited in claim 1 or claim 2, characterized in that a metallic extruded profile (4), having at least one longitudinal groove (5), is attached to each side of the seat (2) and/or the backrest (1).

4. The seat shell as recited in claim 3, characterized in that the extruded profile (4) has a rectangular cross section and a continuous groove on all four sides.

5. The seat shell as recited in one of claims 2 through 4, characterized in that holding elements (16), connecting the backrest (1) to the chassis (15), are mounted in the longitudinal grooves (5) of the backrest (1).

6. The seat shell as recited in one of claims 3 through 5, characterized in that the extruded profiles (4) have a central longitudinal bore hole (7).

7. The seat shell as recited in claim 6, characterized in that the bore hole (7) serves the purpose of receiving fastening elements.

8. The seat shell as recited in claim 7, characterized in that the fastening elements support a headrest.

9. The seat shell as recited in one of the preceding claims, characterized in that lateral support elements (34) are adjustably attached to the seat (2), and the fastening elements (38-41) serve the purpose of locking the support elements (34) in their adjusted position.

10. The seat shell as recited in one of the preceding claims, characterized in that joining elements (8, 12, 27), connecting the backrest (1) to the seat (2), are mounted in the longitudinal grooves (5) of the seat (2).

11. The seat shell as recited in claim 10, characterized in that the joining elements (8, 12, 27) are mounted in the longitudinal grooves (5) of the backrest (1).

12. The seat shell as recited in one of the preceding claims, characterized in that joining elements (21), connecting the footrest (3) to the seat (2), are mounted in the longitudinal grooves (5) of the seat (2).

13. The seat shell as recited in one of claims 10 through 12, characterized in that the joining elements (8, 12, 21) have an articulated design.

14. The seat shell as recited in claim 13, characterized in that the joining elements are composed of two base plates (8, 12) which are articulatedly connected to one another.

15. The seat shell as recited in one of claims 10 through 14, characterized in that the joining elements (8, 12, 21, 27) are mounted in the longitudinal grooves (5) using attachment screws (9).

16. The seat shell as recited in claim 15, characterized in that the joining elements (8, 12) have elongate holes (19, 20) for receiving the attachment screws (9).

17. The seat shell as recited in claim 1, characterized in that the chassis (15) to which the seat shell is attached has an adjustable design.

18. The seat shell as recited in claim 17, characterized in that the chassis (15) has at least one receiver tube (30) and a clamp body (32) which is inserted into this receiver tube (30), the clamp body being lockable in a certain displacement area.

19. The seat shell as recited in claim 18, characterized in that the clamp body (32) is attached to a frame (18) which extends vertically and transversally to the longitudinal direction of the seat (2).

Description:
[0001] The present invention relates to a seat shell, designed in particular for attachment to the chassis of a wheelchair or a stroller, having a backrest, a seat, and a footrest.

[0002] A plurality of such seat shells, permanently or detachably connected to a chassis, are known from the related art.

[0003] Thus, for example, U.S. Pat. No. 4,039,223 describes a wheelchair in which the footrest and the backrest are lockable in different pivoting positions with respect to the seat.

[0004] European Patent Application 911 008 A2 of the Applicant shows a seat shell in which the backrest and the footrest freely pivot with respect to the seat. Furthermore, the backrest is supported by a vertical section of the wheelchair frame. The seat is held pivotably on a slide guide, which allows the seat to move forward, as well as to pivot upwardly. A tensioning device draws the seat back to its surface into its flat position where it rests on the wheelchair frame, the backrest assuming the angled position with respect to the seat. An additional tensioning device prestresses the footrest over its entire pivoting range with respect to the seat so that it is also pivoted into the angled position. The movable seat arrangement described in this Application offers an extremely innovative and advantageous device for disabled patients suffering from spastic extension spasms. In such patients spastic muscle spasms cause uncontrolled extension movements. Prior to the introduction of the object of the aforementioned European Patent Application, these extension movements were absorbed by rigid wheelchairs. The device described in the aforementioned European Patent Application allows the components of the wheelchair to follow the extension movements in a controlled manner by applying an elastic restoring force. The pivot axes of the components of this seat shell are situated at the physiologically optimum pivot points, i.e., the backrest is rotatably linked to the seat in the area of the hip joint, and the footrest is rotatably linked to the seat in the area of the knee joint.

[0005] Finally, an additional seat shell for attachment to the chassis of a wheelchair is known from German Patent 199 30 103 C1. This seat shell has adopted the pivotable connection between the backrest and the footrest, which in this case is attached to the chassis of the wheelchair. In addition, it has thorax truss pads, i.e., support pillows for the thorax, which are attached to the back seat so they are able to pivot transversely.

[0006] The object of the present invention is to provide a seat shell which is particularly flexible and which is adjustable to different sizes.

[0007] This object is achieved according to the present invention in that on both sides of the seat oblong recesses, grooves in particular, running in their longitudinal direction, are situated for receiving fastening elements.

[0008] Oblong recesses, grooves in particular, for receiving fastening elements are preferably also situated on both sides of the backrest running in their longitudinal direction.

[0009] The oblong recesses running in the longitudinal direction are hereinafter referred to as grooves, although it is possible, of course, to provide other recesses such as elongate holes or grooves for receiving the fastening elements.

[0010] The grooves running in the longitudinal direction of the seat allow the displacement of the fastening elements with which the footrest or the backrest are mounted on the seat, for example. Thus, the seat shell may be continuously adjusted to the size of the patient accommodated in it. This continuous adjustability is helpful in particular for young patients, i.e., children and adolescents, who are still growing. An almost arbitrary adjustment for size is possible due to the fastening elements which are essentially displaceable in the longitudinal direction of the seat and/or the backrest.

[0011] According to a preferred embodiment of the present invention, a metallic extruded profile is mounted on each side of the seat. The backrest may also be provided with a metallic extruded profile on each side. As a rule, such extruded profiles are made of aluminum and have an essentially square cross section. Each side face of the extruded profile is, as a rule, provided with a continuous groove which has undercuts. Fastening elements, which positively engage the undercuts, may be inserted into the groove. Furthermore, an additional oblong recess, i.e., a central channel or a central bore running in the longitudinal direction, is situated within the extruded profile.

[0012] Such extruded profiles are mass produced for erecting temporary structures, at trade fairs for example. They are available fairly cost-effectively. Due to the mounting of the extruded profile on both sides of the plate forming the seat or on the plate forming the backrest, a plurality of grooves running in the longitudinal direction may be defined on both sides of the particular plates in a simple manner; fastening elements may be attached in those grooves.

[0013] Of course, after the wheelchair's assembly including the attachment of all fastening elements, the plates and the extruded profiles are to be furnished with padding and a, for the most part, textile protective cover in order to ensure that the surfaces supporting the body of the patient sitting in the seat shell are soft and cannot injure the patient.

[0014] Holding elements, using which the backrest is articulatedly connected to the chassis of the wheelchair, may be mounted in the longitudinal grooves of the backrest. In a preferred embodiment, a holding element, pivotably connected to a vertical frame of the chassis, is situated approximately in the upper third of the backrest. Such a holding element is mounted on each of the two extruded profiles which are situated laterally of the backrest. The pivotability in the preferred embodiment ensures that the backrest is freely pivotable with respect to the surface of the seat shell against an elastic restoring force and, when a spastically disabled person is seated in the seat shell, may follow the extension movements due to spastic spasms.

[0015] Bar-shaped fastening elements may be inserted into the bore in the center of the extruded profiles. This makes it possible that the longitudinal bores of the extruded profiles on the backrest may receive, for example, support bars for a headrest. Fastening elements may be situated in the longitudinal bores of the extruded profiles on the seat; these elements mount and lock adjustable lateral support surfaces to the seat shell which are in contact with the buttocks and the thighs of the patient sitting in the seat.

[0016] Of course, the longitudinal grooves on the seat and on the backrest may receive joining elements on both sides of these components, the joining elements connecting the backrest with the seat. In a rigid wheelchair, these joining elements may be simple, rigid butt plates which are mounted on the backrest and the seat on both sides of the seat. In the preferred embodiment mentioned, in which the backrest, with respect to the seat, is freely pivotable in a certain angle range, the joining elements have an articulated design.

[0017] Of course, joining elements which support the footrest may also be mounted on the longitudinal grooves of the seat.

[0018] The articulated joining elements are, as a rule, composed of two base plates. The first base plate is mounted in the longitudinal groove on one side of the seat using two fastening screws. A corresponding base plate is situated in the longitudinal groove on the opposite side of the seat. A similar base plate is mounted on each side of the backrest in the longitudinal groove being situated there. At their free ends the two base plates each have a bore, a common rotational axis passing through the bores.

[0019] The joining elements for the footrest have a similar design, such a joining element being mounted on each side of the seat in the front area of the longitudinal groove situated there. A narrow base plate, to which the footrest is rigidly attached, is pivotably attached to this base plate. In a preferred embodiment, the footrest may be designed so that its length is telescopically adjustable.

[0020] The joining elements are preferably mounted in the longitudinal grooves using attachment screws. The heads of the attachment screws are introduced into the longitudinal grooves positively engaged and engage the undercuts situated there. Alternatively, the screws may be screwed from the outside into a female thread which is mounted in a sliding block within the longitudinal groove. The sliding block is drawn against the undercut in the groove of the extruded profile by tightening these screws.

[0021] In particular in the plate-shaped joining elements, the attachment screws are preferably introduced into elongate holes which run transversely to the grooves. This makes a displacement of the joining elements in the transverse direction to the groove on the seat and/or on the backrest possible.

[0022] The preferred embodiment of the seat shell is arbitrarily adaptable in a wide range. The fastening elements may be displaced in the grooves or in the longitudinal bores on the sides of the seat or the backrest. In addition, the fastening screws in the long holes on the joining elements may be displaced transversely to the grooves.

[0023] The seat shell according to the present invention is preferably mounted on a chassis which itself has an adjustable design. The chassis may follow the size adjustment of the seat shell in this way. As a rule, the chassis of a wheelchair includes a horizontal support component which carries the seat, as well as a vertical support frame which has handles for pushing the wheelchair and which supports the backrest. If the seat shell is size-adjustable in a wide range, it makes sense to adjustably attach the vertical frame to the horizontal component. For this purpose, the chassis has preferably at least one receiver tube and a clamp body which is inserted into this receiver tube, the clamp body being displaceable and lockable in a certain displacement area within this receiver tube. The clamp bodies are preferably attached to horizontal braces which carry the frame extending vertically and transversely to the longitudinal direction of the seat. In this way, the frame may be displaced in the longitudinal direction of the seat and may be attached to the chassis in any position. Thus, the chassis may follow the size adjustment of the seat shell.

[0024] Embodiments of the present invention are described below with reference to the attached drawing.

[0025] FIG. 1 shows a side view of a seat shell according to the present invention on the chassis of a wheelchair;

[0026] FIG. 2 shows a side view of a part of an alternative connecting device connecting the backrest to the seat of the seat shell;

[0027] FIG. 3 shows a side view of the wheelchair of FIG. 1 with the backrest and seat in the pivoted position;

[0028] FIG. 4 shows a side view of a part of a wheelchair corresponding to the embodiment of FIG. 1, having an alternative connecting device;

[0029] FIG. 5 shows a sectioned view of an extruded profile and a connecting element along section line V-V of FIG. 1;

[0030] FIG. 6 shows a sectioned view of a double brace carrying the vertical frame of the chassis along section line VI-VI;

[0031] FIG. 7 shows a partially sectioned side view of the double brace of FIG. 6;

[0032] FIG. 8 shows a front view of pivoting lateral support pillows attached to the seat;

[0033] FIG. 9 shows an enlarged view of a bracket for the support pillows of FIG. 8;

[0034] FIG. 10 shows a side view of the support pillows of FIG. 8 with a sectioned fastening device;

[0035] FIG. 11 shows a sectioned view of the support surface along section line XI-XI of FIG. 10.

[0036] The seat shell illustrated in FIG. 1 generally comprises a backrest 1, a seat 2, and a footrest 3. Backrest 1 and seat 2 are shown in FIG. 1 without the textile protecting case in which they are usually encased. Prior to use by a patient, the contact surfaces for body parts are provided with padding and encased with the protecting case. This ensures a soft contact of the person sitting in the seat shell with the surface of the seat shell. The padding and case are mostly omitted in the figures for the sake of clarity.

[0037] Both backrest 1 and seat 2 have profiles 4 running on their two side edges. These are aluminum extruded profiles 4, whose cross section is visible in particular in FIG. 5. FIG. 8 shows that a longitudinally running profile 4 is attached to each side of seat 2. Backrest 1 also has a profile 4 on each of its sides.

[0038] FIGS. 5 and 9 show that profiles 4 have an essentially square cross section. A groove 5 is located on each side of profile 4. Each groove 5 has lateral undercuts 6, so that either screw heads or displaceable sliding blocks may be inserted in groove 5 with a positive fit. Profile 4 has a longitudinal bore hole 7 in its center.

[0039] FIG. 1 shows the preferred embodiment in which seat 2 and backrest 1 are pivotably linked to one another. A first base plate 12 is attached to the side of backrest 1 in longitudinal groove 5 on profile 4 using attachment screws 9. Screw head 10 (see FIG. 5) of attachment screw 9 is inserted in groove 5 with a positive fit. A cap nut 11 is threaded onto the thread of attachment screw 9. In the same way, second base plate 8 is attached to profile 4 on the side of seat 2.

[0040] Base plates 8 and 12 are pivotably connected using a pivot bolt 13. On the other side of the seat arrangement, not shown in FIG. 1, a similar connecting device is attached to profiles 4 of backrest 1 and seat 2 located there.

[0041] The bottom of seat 2 is held on chassis 15 of a wheelchair displaceably in the longitudinal direction of seat shell 2 by a displaceable carriage 14; the chassis 15 has a large rear wheel 47 and a steerable front wheel 48 on either side. In addition, seat 2 is pivotably linked to carriage 14. Furthermore, pivotable holding elements 16 are attached to the upper third of both side profiles 4 of backrest 1; holding elements 16 link, pivotably about a pivot bolt 17, backrest 1 to vertical frame 18 of chassis 15.

[0042] As FIG. 3 shows, in the event of an extending movement of a person seated in the seat shell, backrest 1 pivots backward with respect to seat 2 and moves about pivot bolt 17 of holding element 16. Because backrest 1 is attached to vertical frame 18 of chassis 15 by holding element 16, seat 2 must be pushed forward and pivot upward, which is made possible by carriage 14, to which seat 2 is pivotably articulated.

[0043] Pivot bolt 13, which permits backrest 1 to pivot with respect to seat 2, is located exactly at the height of the hip joint thanks to base plates 8, 12 which are preferably used. In the case of a growing person, the position of pivot bolt 13 may be readjusted continuously, because attachment screws 9, which hold base plates 8, 12, are located in elongate holes 19, 20 of base plates 8, 12, elongate holes 19, 20 extending transversely with respect to grooves 5 in profiles 4.

[0044] The same applies to footrest 3, which is supported by lateral base plates 21, which are attached to both sides of seat 2 in longitudinal groove 5. Lateral base plates 21 are connected to carrying elements 23 of footrest 3 via pivot bolt 22. Also in this case, the position of pivot bolt 22 may be adjusted by displacing attachment screws 9 along groove 5 on the one hand and by displacing elongate holes 24 through which attachment screws 9 pass on the other hand.

[0045] FIG. 4 shows an alternative embodiment of base plates 8′, 12′, and 21′, in which a plurality of individual bore holes are situated in bore hole rows 49 next to one another, instead of elongate holes. This embodiment also makes it possible to adjust the attachment of base plates 8′, 12′, and 21′ to profiles 4 transversely to their grooves 5. Lateral support pillows 50 on backrest 1, visible in FIGS. 1 and 4, are known as trunk pads, which support the upper body of the patient sitting in the wheelchair.

[0046] FIGS. 1 and 3 schematically show tension springs 25 and 26. Tension spring 25 draws carriage 14 backward, so that seat 2 is prestressed backward and backrest 1 is prestressed in the vertical, upright position. This prestressing force acts over the entire pivoting range between backrest 1 and seat 2, as well as over the entire displacement path of seat 2. Tension spring 26 draws footrest 3 into the angled position with respect to seat 2, also over the entire pivoting range of footrest 3.

[0047] Should the fastening device according to the present invention be designed to rigidly fastening a backrest 1 to a seat 2, a single rigid base plate 27 may be attached to grooves 5 of profiles 4 on each side of seat 2 via attachment screws 9 (see FIG. 2).

[0048] Fastening elements are also insertable into longitudinal bore holes 7 of profiles 4. For example, FIG. 1 shows that braces 28 for an adjustable holding device 29 for a head rest (not illustrated) is mounted on the upper section of longitudinal bore holes 7 of vertical profiles 4 on backrest 1. One brace 28 is mounted on either side of backrest 1 in the profile mounted there.

[0049] An additional fastening element for an adjustable lateral supporting element mounted in the longitudinal bore hole of profile 4 is described below in connection with FIGS. 8 through 11.

[0050] FIGS. 6 and 7 first show the adjustability seen in FIG. 1 of chassis 15 of the wheelchair. Vertical frame 18 is adjustable in size in the longitudinal direction of seat 2. For this reason, vertical frame 18 has, on its lower ends, two double braces 31 which are each insertable in a double tube 30 of chassis 15. Each brace of double brace 31 is hollow and, at its end, has a clamp body 32 resting on the oblique end of brace 31 via an oblique surface. Clamp bodies 32 may be drawn against the ends of double braces 31 using two draw spindles 33, so that clamping occurs within double tube 30, and vertical frame 18 is secured on chassis 15. As mentioned previously, such double tubes 30 in which a double brace 31 of vertical frame 18 is mounted are located on both sides of seat 2.

[0051] FIGS. 8 through 11 show a novel fastening device for adjustable lateral support elements 34. Each support element 34 has a folded metal sheet 35, to which a pad 36 is attached. Each support element 34 is attached to a section 4 on one side of seat 2 using two brackets 37. As can be seen in FIG. 10 in particular, a connecting sleeve 38, obliquely parted in the center, on whose two parts the two brackets 37 are non-rotatably attached, extends in each section 4 within longitudinal bore hole 7 with little clearance. A threaded rod 40, whose threaded front end is screwed into a clamp body 39, extends within connecting sleeve 38. The end of threaded rod 40 projecting outward carries a screw head 41, which is positively engageable with a wrench. The screw head is located on the front edge of seat 2 near footrest 3 (see FIG. 1). Clamp body 39 is displaced in the axial direction toward connecting sleeve 38 by twisting threaded rod 40. It is also displaced radially outward over the oblique surface of clamp body 39. Likewise, both connecting sleeves 38 are displaced radially with respect to one another over their oblique surfaces and are clamped within longitudinal bore hole 7 in section 4 on seat 2. After tightening threaded rod 40, brackets 37 are fastened essentially rigidly to section 4.

[0052] Support element 34 may be locked to the upper end of brackets 37 in a similar manner. As shown in FIG. 11, a draw spindle 42 is located within distance sleeves 43, 44. The front end of draw spindle 42 has a screw head 45. When draw spindle 42 is tightened, folded areas 46 of metal sheet 35 are clamped into slits 47 within brackets 37. Both screw head 45 of draw spindle 42 and screw head 41 of threaded rod 42 are located on the front end face of support element 34 and of section 4 on seat 2. Each support element 34 may thus be adjusted as desired both in its inclination and its position in the transverse direction of seat 2.

[0053] As FIG. 8 shows, support elements 34 may be adjusted to different body widths in a broad adjustment range. Pads 36 of support elements 34 may also be set at an angle to one another, so that they enclose a trapezoidal space widening downward, for example. The support elements, which are also known as adduction guides, not only exert a lateral support force in this position, but also a holding force on the hip and legs of the patient sitting in the wheelchair that prevents the patient from slipping out upward.

[0054] Extruded sections 4 are attached to backrest 1 and seat 2 in any suitable manner. They may be directly welded onto metal plates forming backrest 1 and seat 2, for example. A detachable joint, however, is also possible. FIG. 9 shows, for example, a threaded joint in which a connecting screw 51 is screwed into an internal thread of a sliding block 52, mounted in a longitudinal groove of section 4, through the metal plate forming seat 2. Such threaded joints may be situated at different points along the length of section 4.

[0055] List of Reference Symbols

[0056] 1 backrest

[0057] 2 seat

[0058] 3 footrest

[0059] 4 section

[0060] 5 groove

[0061] 6 undercut

[0062] 7 longitudinal bore hole

[0063] 8 base plate

[0064] 9 attachment screw

[0065] 10 screw head

[0066] 11 cap nut

[0067] 12 base plate

[0068] 13 pivot bolt

[0069] 14 carriage

[0070] 15 chassis

[0071] 16 holding element

[0072] 17 pivot bolt

[0073] 18 vertical frame

[0074] 19 elongate hole

[0075] 20 elongate hole

[0076] 21 base plate

[0077] 22 pivot bolt

[0078] 23 carrying element

[0079] 24 elongate hole

[0080] 25 tension spring

[0081] 26 tension spring

[0082] 27 rigid base plate

[0083] 28 brace

[0084] 29 holding device for head rest

[0085] 30 double tube

[0086] 31 double brace

[0087] 32 clamp body

[0088] 33 draw spindle

[0089] 34 support element

[0090] 35 metal sheet

[0091] 36 pad

[0092] 37 bracket

[0093] 38 connecting sleeve

[0094] 39 clamp body

[0095] 40 threaded rod

[0096] 41 screw head

[0097] 42 draw spindle

[0098] 43 distance sleeves

[0099] 44 distance sleeves

[0100] 45 screw head

[0101] 46 folded area

[0102] 47 rear wheel

[0103] 48 front wheel

[0104] 49 bore hole row

[0105] 50 support pillow

[0106] 51 connecting screw

[0107] 52 sliding block